I think it would make sense to differentiate antinatalism the philosophy, which is basically a very narrow philosophy that suggests that being born sucks even if you are privileged and doesn't suggest any totalising course of action, and antinatalism the reddit meme, which as I pointed out in another reply kinda sucks.

I share your concerns that this kind of rhetoric is going to be used by the right, but antinatalism as a stand-alone thing seems to have been born in the 2000s and I feel like "the poors shouldn't breed as much poors for their own sake" is an older idea than that.