Straight man here. A gay character trying to get rid of straight people sounds really bad, but I like to play devil’s advocate so I’d like to approach this discussion with a different perspective.
Often in story telling the antagonist is a representation of the lesson to learn within the story. So there is something about the villain you don’t want to have be it an ideology, attitude, or viewpoint.
So, what if we keep this scenario but every other representation of gay characters in the story are well represented and there is a lot of other representations of it? At face value, I’d think this would help balance it. At first I actually did think this would help solve it, but the more I thought about it, the more it falls apart.
So from here I took that same set up but reversed it. If there is a straight person trying to get rid of LGB, but there are a lot of other characters who are straight but are not homophobic, wouldn’t that give a message that the villain’s viewpoint is wrong, but not that being straight is wrong, right? I’d say, yes.
However, these two are not the same since LGBTIA has negative stigmas within some cultures and being straight does not. So I think showing a broad range of good representation would help fight the negative representation of the villain (that’s kind of the point of the four point opposition in the video I shared), but it would be better to avoid that negative representation.
What I’d do instead is recommend is to analyze the role of your antagonist, @MoonlightBomber. If you need a set up where someone is trying to get rid of straight people, can you do it with a straight person? Do you just want a villain who is gay? Then could you have them being gay have nothing to do with their villainy? Is is actually about having a villain who is genocidal and you’re looking for a different genocide than is normally talked about? Then is there a different type of genocide you could do instead? Like gynocide which is rarely talked about.
In the end, what is the point of the antagonist you are looking to write? What aspect of their character is important for the story you want to tell? Then try to figure out different approaches or directions of those same aspects.
So to try to make it easier try to fill in the blank of the following sentence (and keep it to a single sentence).
This antagonist is in my story because I need a character who ______________.
If you put “is gay and is trying to kill all straight people” then you have a big uphill fight on a hill you are creating when it comes to fighting the negative stereotype.
If you put “is gay” then that tells you the character doesn’t need the negative stereotype.
If you put “is trying to kill off straight people” then you should find a way to do it without the negative stereotype.
If it is none of these, then you can easily avoid this.