Phobia means fear or hatred. And in psychology, that means it's a type of anxiety, and people often make jokes about what causes them anxiety, as a way to control that anxiety.
And I don't think that McGibster feared or hated gay people back then or now. I think they were following societal trends that made that sort of joke--you can't trust gay men around you because they will have sex with you no matter what--"acceptable".
Since that sort of joke isn't OK now (either as a gay joke or as a rape joke), it's considered to be bad, or at least in poor taste, for writers to include the lead-ups for those sort of jokes. If people want to make those jokes on their own, you can't stop them, but it doesn't mean it's OK for other people to do the set-up (dog whistles) for those jokes.
But you can claim my argument failed because you disagreed with it?
So you're saying that one could very easily make a Dark Sun game without any sort of slavery in it and it would still be Dark Sun?