Does it worry you that most of the people on /mu/ are just people from this place now?
It's been that way for a while, sadly. I'd actually say that they're partly responsible for the poptimist/waifufag takeover of /mu/ a few years back.
Their taste in music is really bad, which is funny considering that their community was birthed from making fun of kids with bad (but better) music taste.
It's hard to imagine /mu/ without the lwg poptimism and memerap, honestly. So no, it doesn't worry me in the sense that it's any inconspicuous fact that this board is mostly underage teenage redditors.
I'd assume /mu/ has more overlap with indieheads whereas lewronggeneration is a bunch of tumblr poptimists who would jerk off to Grimes if they weren't ashamed of their sexualities.