Why am I the bad guy?

You are not the bad guy .
Dementia is the bad guy . It can make a nice person not nice , or a not so nice person worse.
Sorry to say , the one who helps , often takes the brunt of their unhappiness .

My mother was like this too . I called the local County Area Agency of Aging . ( I looked on the county website under services for elderly or something similar ) . The social worker told me “ Stop helping her , let her fail, so she sees she’s not independent “. The social worker came out and interviewed Mom . She Asked Mom , What if ……happened “. Mom “ could not come up with a plan” for various scenarios and the social worker deemed her unsafe to live alone . I had already picked out an assisted living but could not get Mom to go . The social worker was willing to come back 2 weeks later with “ help” to physically remove my mother from her home and bring her to assisted living .

OK..here I go.
I am a firm believer that a person with dementia should NOT be living alone.
It simply is not safe.
Your mother has no concept of safety. Of reality. This is evident by her accusations.
Is anyone POA?
If not at this point someone would have to be appointed Guardian. that can be a family member or the Court can appoint one.
Someone has to pull up their "big boy/girl pants up" and make the decision that mom either needs a full time caregiver OR mom needs to be placed in Memory Care. And mom has NO say in this decision.
No one WANTS to leave their home but at some point a decision must be made based on safety.
YOU obviously can not be her full time caregiver since she pushes your buttons. This is not good for your physical or mental health.
Are either of your siblings able to move in and be a full time caregiver?
I think it is time to have a sit down talk with your siblings and an Elder Care Attorney.

Ugh. I know.
Before we knew my aunt had dementia, my cousin (her other niece) who lives close by and cares about her deeply, all the sudden became the bad person. I didn't comprehend. Aunt called me one day and told me she was threw with her. Shocked, I asked her what happened. She never gave me a clear explanation. I was shocked. Then a few months later, I get a note from my aunt's neighbor asking me to come by and check on my aunt. She no longer trusts my cousin who lives near her and doesn't want any parts of her. She was accusing her of stuff that I knew wasn't true, such as letting people in her house. It was baffling.
So because of all of this, my aunt decided I would be her medical POA even though I am far. I had no idea it had stipulations, such as being at her beck and call, as well.
I did what I could, as I love my aunt, too. However, it was becoming unbearable and aunt wouldn't listen and wanted everything her way or no way. I saw myself paying for everything, and mind you, my aunt has the money. She even tried to make me pay for her caregiver. I was expected to give up weekends or worse yet, go and move in with her.
I had enough. ENOUGH! I gave up the POA, gave up my visits and now I am the bad person, which I knew would happen sooner or later.
Like your mom, when I would call her, she would get mean towards me or not answer at all. She wrote me off, and that hurt, but at the same time, I had to look out for my well being and peace. So, you may need to step away from all of this like I did. I have no idea how she's doing now, but I know it can't be good. Like someone mentioned, dementia is a wild ride. I had no idea I would experience this. I didn't see it in my parents until my aunt. The changes, the personality, even her looks changed drastically. It's just so sad, and I'm sorry you're experiencing this. You're not alone and I wish peace and serenity.

She is consuming your life from what you have written. For your own mental health/sense of inner peace, it would be better for you to detach somewhat. Do you think that she would be open to daily in-home support? That would give you something of a break from her. The PSW could also see that the cats are correctly fed. Too much of this is falling onto you, and it is having a deleterious impact on your well-being which does matter.

Your Mom should not be alone. If you can't have her living with you, which is OK, she needs to be placed where shebis safe.

When my grandpa was diagnosed with dementia I was relieved because his already terrible attitude had gotten unbearable. He started making all kinds of crazy accusations against me and my husband even though we are all the family he has left ( most threw in the towel well before the diagnosis) Whenever he can he claims I am stealing from him and has even reported me to APS a few times. It sucks to have someone you gave so much of yourself for treat you so poorly. Buckle up because dementia is a wild ride for whoever remains around. I’m pretty much to the point that I do my POA duties and protect my peace. Staying away from him has been the best for me. I have visited once and spoken to him 3-4 times since he was placed in a MC facility. Each time he claims he has never made accusations against me but then he does it over and over again. I know it’s mostly the disease but tbh he’s been a miserable person for years and it will only get worse I fear. I hope you are able to get as far away from all the stress this can cause because it will definitely take a toll on you.

Well, Julie, you're pretty bright, so I know that this is either the dementia talking OR Mom's always been a bit of a pill, and still IS! Take care, hon.

I was the designated Bad Guy for my mother too, especially after dad died. He was the Bad Guy for the entire length of their marriage, then it switched to me. Someone has to be It, so why not You? I took on the role bc mother was like a child anyway, always having to be told what to do and once dementia set in, it was even worse. She lived in AL and then Memory Care Assisted Living, thank God, so she was safe. I was POA so I got to make the decisions FOR her, and I did.

I'd call APS as suggested bc mom is NOT safe alone, especially cooking. Don't take what she says personally, if possible, and let APS decide she needs placement. You'll still be the Bad Guy, but who cares? She'll be SAFE.

Julie71, I understand and relate to your situation. My mom is 90 and I have been taking care of her for over 11 years. I started helping her when I was a child as she was always upset about something, always playing victim and needing all around her to focus on her. She also has ODD undiagnosed but I was in the psych field for years and recognize it. It is very hard to get away from this as we want our parents to be well taken care of. I can't really advise you but I can tell you what increasing your time helping someone who treats you this way may do. I am at my wits end and unhappy daily. My mom is argumentative, refuses to follow any orders including medications, meals, etc. She is getting worse and worse because of her lack of compliance which means I have to do more and more to coax her into doing what she need to do. She has had some kind of dementia for over 16 years. She still lives alone but I am over there every day sometimes twice or 3 times a day depending on the crisis. She attempts to turn anyone around into her slave and expects them to do more and more for her while she lounges around the house doing nothing. I know it is the dementia because she can't even feed her cats correctly which is why I go over there daily to make sure they are fed (she gives them potato chips, fruit, nuts even though I have notes telling her what to feed them and even though I call her every 2 hours all day long). I am at the point of hoping I die soon except her cats and my cats would not be able to take care of themselves as they are old and two are special needs cats. It is demoralizing, depressing, degrading to always be put in the wrong no matter what you do to help. It is the ultimate insult to help your parent or anyone who ridicules you and manipulates you into doing more and more or is never appreciative. Mom has enough money to go to a home for several years. I do not have much money due to my home being flooded during Harvey but I retired and worked contract and was able to pay off my house and car. Mom tries to make me pay for everything and does not pay me back at all. She will say "well, you paid for it so you must have wanted to." When I ask her if she will pay for dinner for us both if I pay for ballet tickets she then does not. She simply will not pay for my meal and she makes me pay her tip and my tip as well. Ballet, opera and plays are not cheap. I have paid for every one. So now I have told her no more plays or ballets unless she can stick to her agreement to pay for both our dinner and tips. She cannot so I will be going with others, not her. Everyday is a yelling and screaming match as I remind her to feed her cat what is on the list, chicken (which she decided to feed all her cats for year), cat food, tuna, kibble, water, cream for a treat. When I arrive and show her the bowl of potato chips she left for her cats to eat she yells at me saying she did not do it, someone else did. Then she tells me how I have never liked her and I pick on her and only want the worst for her. Funny I have driven miles to get her hyperbaric chamber treatments, taken her to my doctors (I was in med field so I have good docs) with the docs ending up telling me they are not happy with my mom's behavior. I had her on research protocols with success but she can't follow directions or take the meds even with my calling and telling her what to take at this moment while I am on phone with her; she does not. She is getting worse and I do not have energy to deal with the meanness, self aggrandizement, usury. My life feels meaningless if I'm not helping her (or my brother who is her clone). If you continue trying to help your mom when she is not nice to you, it will eat away at your self esteem. I have many accomplishments I achieved with no help, but the meanness is overpowering. I let of things important to me go that I cannot go back to now (played in orchestra-quit). Don't do what I did. If she is disagreeable around you, stay away.

You can't reason with someone with dementia no matter how hard you try. And that doesn't make you a "bad guy."
What probably needs to be done now is for you to call APS and report a vulnerable adult living alone with dementia, and allow them to come out to do an assessment and if need be take over her care.
Your mom should NOT be living by herself, and APS will make that determination, so make that call sooner than later.

You are not the bad guy, her brain is broken, I would cut back on my visits and regain your self-esteem, dealing with someone in her mental state will send someone to a place they never would want to go.

Don't give up you, for her, back off, set your life direction understanding that it doesn't and shouldn't revolve around her.

You do not have to condescend to her and her behavior.

I'm sorry your mom's illness is manifesting in this way. Dementia doesn't make sense. You're not the bad guy.