@Moodyz Your real world is a sadder place than my real world, or so I feel.
But that aside, she ain't interested in Anime/game music, but what he's listening to. And plenty of anime/game music is going mainstream too by now, being played in concert halls by full orchestras. So the call you cited is the call of narrow-minded people who will call out everything that differs from them in that way. Be it color, language, dialect, age, gender etc. and whether they see the world as binary or divided into a million fractions.
..
Come to think of another thing - yea, girl's defo claiming ownership of the boy. "Only I can see him so he is all mine" kind of ownership.
I wonder what'll happen next. Either nothing (one-off rom-com jokes forever), she becomes even more possessive (scary girl world) or he learns to take a bit more space in the world (meaning she can and will have to pull back just a little, meaning still drama but fewer dead household pets)