not something I've dealt with that much but have definitely noticed this behaviour all over the kpop community
kpop fans/fandoms seem to be REALLY harsh about people who state they used to like the same group and be in the fandom but stopped for some reason, even if they explain the reason properly and it makes sense
if its about the negative reason behind their not being a fan anymore, I mean, OBVIOUSLY something negative had to have happened for them to stop being a fan in the first place