I think it's 'cos men are meant to be strong, powerful and composed at all times, but being gay or saying something that is construed as gay is a sign of weakness.
Women, due to our history, are pretty much expected to be the weaker sex, thus it doesn't compromise their position if they admit to gay thoughts or feelings.
It's a stupid double standard, I don't think there's anything wrong with either sex admitting that another guy or girl is 'hot'. But, society frowns upon it.
I've always been very open and honest about sex and sexuality so at school when I'd comment on a woman being hot, or gorgeous, or beautiful, I used to get the weird looks too, and rumours kinda circulated about me. But I ignored all of that stupidity, 1. Because I won't be scared into not expressing these thoughts and 2. I hate the fact that people need to label themselves and others. If you're a guy into other guys, I wouldn't label that person as 'gay' because that person is too complex to be labelled regarding one feature of their personality and biology and, really, it doesn't matter. They're not gay, just a dude that likes other dudes to me.
On topic, my girl crushes include Lady Gaga, Nigella Lawson, Cristina Scabbia and several others I can't think of off the top of my head. I consider myself pretty much straight (although I'm not convinced that there isn't a little bit of lesbianism/bisexuality in there somewhere, for the right woman) but would 'go gay', for want of a better phrase, for these beautiful ladies.
I also don't get why people have to 'come out' as though it's a huge deal. Your sexuality isn't anybody else's business, it's very personal, so what does it matter whether you're gay or straight? I didn't come out to my family and friends as 'straight with probably a little bi', because I don't feel the need to. It's my business alone. Society puts far too much pressure on young people, and the fact that Gay Rights activists are becoming much more predominant means that kids think it's 'cool' to be in this minority, which causes a lot of confusion. There's no rush for teenagers to decide whether they're one or the other, but they worry far too much about the implications and other peoples' reactions.
I know, maybe some parents and people aren't as laid-back about sexuality as I am, so some parents may have hammered it home that homosexuality is 'wrong'. This kind of attitude needs to be eradicated or, at the very least, acknowledged for the poisonous bile it is, so that people can just be whoever they are/want to be, rather than having to be identified by something so...superficial, for want of a better word. It doesn't change who you are as a person, so why should it matter?
Sorry, /mini-rant