Why are teenage anime girls always the ones to have designs that only an adult woman should wear?

Let me explain for example in My Hero Academia Momo super hero costume looks like what a stripper would wear even though she's 15 but what's even more worse is in Demon slayer Nezuko demon form looks too revealing for a 12/14 year old girl to wear and even Daki who's 113 or technically 13 shouldn't be wearing it even if her age is 113 because her human age is 13. Am I being a tight ass or does anyone agree that a lot of these authors in mangas which later become anime's usually but not always seem to be too comfortable sexualizing minors.