I really don't get what your problem is here? There will always be an assumption someone who wears feminine clothing is gay, what's the issue with that? Why does it make you so angry?
What is "feminine clothing"?
I can genuinely say I have never ever seen a gay man wear a dress or some kitten heels etc unless they are drag acts etc which is a job more than a way of life!
I am sure some do it, but most gay men dress in "normal" clothes in their every day life. As they should do as they are just normal regular people! Some may glam it up at Pride etc but that is no more of an indicator as assuming that I wear a bow tie and suit because I went to a posh do (doo? )once.
There are so many mad misconceptions about the gay community.