One of the biggest constants with women, is that it's very rarely about THAT SPECIFIC THING, it's almost always either
(i) what that thing REPRESENTS to them, or
(ii) a CONVENIENT EXCUSE to argue because there's some other issue(s) that have probably going on for a while,
or both.
My guess is that she had already been losing attraction for you for other reasons anyway, and she picked up on the hair situation, which represented your lack of alpha / manliness in some other incident(s), and so she picked on it, partly because the resentment was building up, and partly to test you and see how you'd react.
Personally, if a girl asked me if I was gay during sex, I would likely either just laugh, or use it as a bit of banter and turn it into dirty talk, "yeah I'm so fucking gay, all I wanna do right now is fuck the shit out of you, that's how gay I am..." etc.
That said, this thread is a great advertisement for using dirty talk properly. She shouldn't even have the time to be bantering you in the first place, because you should be telling her how you like it, asked her how much she loves being fucked by you, and getting her to scream like a dirty slut for you

My favourite sex technique guru David Shade has a new programme all about using advanced hypnosis techniques to make dirty talk into a powerful tool for increasing her sexual pleasure, check it out here
http://masterful-lover.com/cmd.php?Clk=4300347