Heterosexually vain

I recently got into a bit of a discussion with a gay coworker of mine while I was on my lunch break. It included the following exchange.

Me: I prefer the fall because I think I look better in cold-weather clothes than in summer clothes.

Christoph: Why should you care how you look? You're not gay.

Me: Hey, straight guys are allowed to be vain, too.

Christoph: Nope, I'm pretty sure that's our prerogative.

Me: You can't just take that from us.

Christoph: It's done.

Me: Not cool, dude.

Christoph: What do you mean? You only have to attract women.

I can only assume Christoph was implying that men are harder to impress than women. I'm fairly certain that's the gayest thing I've ever heard anyone say.