There's a guy I met back in college. We weren't close, but we played D&D and got along well. He was always quite conservative, but knew how to show basic respect to people. Lately, though, he's been going off the deep end, and seems to have gotten hooked on radical right-wing stuff, specifically Steven Crowder. After something particularly horrible about transgenderism he shared on Facebook today, I finally called him out on it. Normally, I just block people like that, but I can't bring myself to do it this time. I genuinely care about him, because I remember what he used to be like. And I know there's not much I can do to help him. It's just frustrating to watch someone go up in flames like this.
Part of it may just be the election cycle - it's a particularly bizarre and contentious one, and your experience is probably not unique in the States right now. That said, it doesn't excuse his behavior - I think it's a good idea to call him on it and try to have an honest conversation, given that he's your friend and you recognize that this is unusual for him. If he's able to reign it in, then great. If not, blocking their social media posts for the sake of preserving the friendship/acquaintance in the long run might not be a bad idea.
Sometimes people dig holes like that for themselves... I've watched acquaintances (former friends, but I now refuse to call them that) go the same way. So yeah... Just know your own boundaries. Don't follow him down and let him talk badly about trans people to you. And like Gravity^ said, if he's being obnoxious on social media etc., block his content.
