>>125330911They don't just mock "sexy" designs, they mock all old designs (except ones that have been in movies like Spider-Man, of course).
It's literally just because they look silly in live action. They make fun of Falcon and Luke Cage's old designs, Iron Man's metallic tights, Cap's pirate boots, Robin's shorts and elf shoes, on and on and on. It has nothing to do with being "sexy". Stripper outfits just also look silly and have no practical purpose.
Now, I'm not saying that's right, I like the old outfits and hate movies, but it's not some evil SJW agenda specifically against you.