Straight men pursue women all the time who have no interest in them whatsoever. That has never stopped them. Why should gay men not take the chance and shoot their shot? I think straight men should take it as a compliment as long as its not done in a disrespectful manner. I don't think a gay man complimenting or approaching someone who is "straight" is inherently disrespectful, but the way it is done can come off that way.