I'm not trying to say there's something wrong with that. But don't extol it as a virtue. If a gay guy is willing to fuck anyone with a penis, that doesn't mean he can congratulate himself on not being shallow, unlike those guys who only go for certain types.
However, I'm not saying bisexual=low standards. But bisexual people, on average, are less picky than monosexual people, simply because they find twice as many people attractive as they would if they were either gay or straight.
But, now, you say "if a gay guy decides to be a total slut," as though it were a choice. AS if to say that people don't choose to be gay, straight, or bi, but whether or not you're attracted to someone of your preferred gender - that's a choice. But I guess a guy could choose to suck every dick you could find, regardless of his sexuality, since that doesn't require arousal on his part. But why someone would want to, without some additional incentive, such as money, I have no idea.