well i experience a little bit of that every day since i have been 24/7, and since I've identified as trans-femme, I think ultimately both comes from the same root fear of undermining masculine privilege and values.
i still feel like the majority of people have a 'as long as you keep it in the bedroom' attitude towards homosexuality, which is still a latent form of homophobia. just the fact that people have to insist to someone that they aren't gay or that it's often the first question or concern out of someone you come out to shows that there is a broad, latent homophobia embedded in society. A lot of crossdressers I've talked with, when I tell them about my experiences with men (I am pansexual), will very quickly jump assure me of something like "Oh for me it's just dressing, no gay stuff, OK?", and I've heard many stories of "Don't worry [insert relative here], I'm not a fag, I just like wearing women's clothes".
It could also be some form of sexism (man and woman are immutable things, women ought to like men, men ought to like women, so if you dress like a woman you must want men like a woman ought to)





