Seems like a lot of projection going on here. K-pop idols spend a lot of time to make sure their onstage performance and stage presence are topnotch. This includes aspects such as putting on the right facial expressions and executing precise dance moves. Why is it wrong for a K-pop fan to do exactly what a K-pop fan is supposed to do?
You're missing the point of fancams if you perceive them that way. Fancams are like highlight reels, no different from sports cams that focus specifically on one athlete's performance. It's only weird if you make it weird.