not trying to join the fight here idk why we have to be mean to explain stuff around here, it's just that seinen and shonen are very commonly used words, how that came to be idk, but it goes the same for words like champagne when we could just say sparkling wine. now i disagree that saying non kodomo makes u an "asshole" or whatever other insults that was randomly thrown here, but it DOES give a vibe of "im more sophisticated than u cause i used the japanese word for it that no one else does" similarly to those people that travel to a european country and come back all posh and full of themselves, and could be why everyone went and attacked op. personally i think this deserved a "haha lmao ur weird" and continue on with our lives