Just look at fitness influencers, atheletes, male and female who have peak human bodies as examples, ppl like showing off their bodies when they are physically fit and look good.
I never got the whole oversexualized angle when it comed to most comic book appearences, they look very tame compared to rave or even gym outfits meant for mobility, do superheroes not need mobility?
tiger and bunny is a commercialized approach to superheroes and in that case they do sexualize themselves on purpose (men and woman) since they are eseentially influencers trying to get sponsors. (They wear ads on their supersuits and get sponsors for gadgets)