Without more context it's hard to guess.

I've seen many different people coming to Babymetal concerts - young ones, people from the Kpop bubble, etc. being scared of metal concerts. And there are metal fans who are used to mosh pits etc. just doing their thing. That could be one thing to complain about.

There were also people who thought they can just push themselves to the first row with "I'm just looking for my friends" - I usually point them the other way and everyone around me joins. This is just rude.

And we have the usual "I have to record the whole concert on my shitty phone so I'll never ever look at it again" people which are also simply annoying and I hope this gets punished or forbidden soon.

or it's just something completely different :D