They may very well have met multiple trans people and never even known it. Their hatred for trans people is really just for the ones who can’t “pass.” They don’t think about the others. They think of “a man in a dress.” If you showed them a picture of Valentina Sampaio without saying who she was, they’d say she was a woman. And it would be fun to see their reaction when you told them she was trans because at least some of them would see her and be aroused.