Why should our interests ever have to change just because we get older?
As a kid I listened to Nirvana, as an adult, I still listen to Nirvana, as a kid I played video games, as an adult, I play them even more than I did as a kid.
If I, a 22 year old man, want to watch a shojo anime starring various Japanese schoolgirls, then that's my right as an American.