harassment like this happens with underground idols in japan too because they can’t afford the security mainstream idols have :’(It's a thing that happens to Kaigai/Overseas idols. Lots of people verbally harrass and online harrass them for being "cringe".
Fans usually band together to remove people like that from the community by not selling tickets to them, blacklisting them from events, making sure word spreads out. If they do that to one idol, they're probably doing it to another.