(Note: This isn't necessarily aimed at another specific post that's on here atm, it just got me thinking.)
It feels like these type of memes have been cropping up more the last few years especially, and that they're an expression of nervousness from a culture anxious about how dramatically the popular perception of gender/sex is changing.
I think you're exactly right. And I think that's being done with racism too. There are lots of ways to meme that can't be easily diagnosed as overt racism or sexism, that still serve to reinforce racist and sexist attitudes because they fall in these in between spaces.