“Gay” is not an insult when used to describe a gay person. :-) Let me clarify. When somebody says, “that’s so gay” to mean that something is bad or undesirable, that is an insult. Because, of course, nothing is wrong with being gay.

By the way, most (if not all) anti-gay insults are rooted in disdain for women. When cis/straight men (and some women) express disdain for gay men, they almost always do so by comparing us to women, by observing that we are like women.

But the thing is, you have to be a misogynist for those jokes to even be coherent. If the person slinging the insult didn’t have anything against women, then the insult wouldn’t make sense.