it's not like the red headed brat was the only one who was talking shit and harassing MC, everyone was against him before he left including the other leaders so why is all the blame put on the red head?
There are followers and leaders, the followers are generally only as shitty as their leader allows. with that in mind, have knows a few people like that where the leader moves away and suddenly the followers are no longer shits.
It also doesn't hurt having it shoved in your face how important the person was.