I'm so sorry it took me so long to circle back! Had a sick pet emergency here again, which then resulted in a no-sleep issue on my part and just messed up my whole week. I'm sorry it meant you had to wait on me.
You know, you said something about your Dad that sounds SO like mine in some ways:
Your saying that the idea that identifying as non-binary is a conservative idea is pretty accurate in most cases, but when my dad started talking about free speech and all that, it was strange because he normally condemns stuff like that. It really showed another side of him that I'd never seen before, and don't like at all. It really cast him in a new shadow, where I can't be myself in front of him. That's all new because my parents were always pretty good with lgbtq+ stuff, though not the bi/pan or gender topics. He was my person, but now I'm having a hard time with this.
We literally spent the first six years of my life in hiding because of my father's very radical leftist politics. My father was a white man who was helping with civil rights movement work in high school in the 60s, and anti-war work right before I was born. I grew up so schooled in social justice it has always felt like part of who I am. And, like with you, my Dad always felt like my person. We always understood each other. And he was great about my queerness, always. Coming out didn't even feel like coming out with him: it was literally nothing, it was easy.
At the same time, like with so many human beings, my Dad isn't perfect and he has ;political blind spots. His feminism, for instance SUCKS. So sucks (even though he actually doesn't even like men and is lovely to women). During the 2016 election, he was one of those folks that would not STFU about Hillary and was all over Bernie and how he would vote for Warren if she was running, but of course, just as I predicted and told him at the time I knew would happen should it come to pass, once Warren WAS actually running he had radically different feelings. His gender politics just plain suck, so it's not actually surprising to me that he's clueless when it comes to my gender identity.
What I do for myself around it is remind myself that he's human and even though I looked up to him he's not and has never been perfect and he by no means is always right about everything, and, in fact, there are plenty of things I have better awareness about than he does! There are some things he just won't ever understand, including some things he won't work to understand because he just won't get them for whatever reason. I remind myself it's his problem, and about him, not me. I don't talk to him about it because I know it would just frustrate me and I wouldn't get what I want from it: it would make me feel worse, not better. I don't think of it as keeping secrets -- it's not -- so much as just not making myself more crazy than I need to, just like I don't talk to my mother anymore about wrongs done in my childhood by her because I know she can't give me what I want from that.
Is any of that helpful?