I find it odd it even has to be said, though. Like, what situation warrants it? Besides being in a Kevin Smith movie or a Knocked Up budz-juzt-hangin' out scene?
I'm not saying everyone should be open to accept flirtatious nods here and there from the gender they're not into, or the fact you genuinely don't want gay people hitting on you, if anything because it could make an incredibly awkward situation (Oh, Withnail and I). Just that line.
"I don't have a problem with these gays, but if one tries to come on to me --"
Seriously, any variant of that.... Nothing comes off incredibly douche baggy?
Also, your ending of the phrase isn't as bad as what generally follows. But I don't know, I've just heard so many slobs say that. It's generally, "I don't have a problem with gay people, unless they hit on me". Seriously. I just dislike that whole, "People can do whatever they want in the privacy of their bedroom" type of attitude towards homosexuality. Like, it can exist, just not anywhere near/in front of me. It just feels like thinly veiled "I guess I gotta" acceptance of homosexuality.