I'm so sorry your mum isn't able to give your feelings the space and respect they deserve. You're completely right. And fact is undeniable, he didn't deserve anything, other than what he advocated for all his life. Also your mum is probably just grieving or feeling socialitically pressured to grieve. How your mum is feeling can be entirely separated from the person she's feeling that for. Don't address the person she's grieving but maybe you can offer her kindness for her feelings, which, I'm assuming would be adulting beyond your developed years. Put clear boundaries down that you aren't changing your opinion on the subject, nor do you want to speak of it, but you care about how she feels. Because people's feelings matter, regardless of whether they're perceived by others as being about unreasonable things, and maybe that will help her learn to be more emotionally supportive, at very least, it'll set a good boundary for you and how you expect her to treat your feelings in future. My mum is a bit like yours, I've never found a good balance, and I can barely speak to her, and I've had many many years of no contact at all, it's hard to go through, I wouldn't wish it on anyone, but sometimes that's the path you end up on, after exhausting all options available at the time. I hope you're able to find a way to co-exist, more peacefully than I was able.