I thought NDT had a really useful take on issues like this. He said something to the effect of "you may not like it but you do at least agree they exist, right?"

I think that's a helpful lens to look a topic like transgenders. Even if you disagree with a lot of the things they stand for, you can't argue they don't exist. And if you start from a standpoint of "yes they exist" then maybe the next step you get to isn't "but gender is a fact". Maybe the next step is something like "ok they exist, maybe I can understand their experience a little better". Or maybe it's "I don't quite understand so maybe I just won't speak on it".

Also, let's be honest, maybe it's "I get it and I know they exist but I wish they didn't and I'm going to say bad things about them because I don't like them."