I find that "weak" reason as to why he avoid "committing" social relationship very solid enough.
One day of "betrayal" and going down like that? Yeah... that happens... a lot in reality tbh. Like it happens a lot in children's social circles.
Did MC and his Mother handled it perfectly? Yes and no. Yes as MC got out of that place, who knows if it'll get more toxic or not. Also it is a major no, like what others said above, they just ran away from the problem but... it ain't a bad solution after all. Not the best but clearly not as worse as people make it seem.
I really can't speak for others in this comment section but I've been there both in MC's position and early, the supposed to be the target of bullying's position. So I'm at least relating to him at a personal level. Not that there's any more closeness than that. No harem and no cute Rei afterall... xD
Like
@quagzlor said, yeah it f---ing hurts a lot as a kid to actually realized you just got betrayed by those who you trust a lot as a kid. Yeah at that point in life in childhood, I can't even trust even my parents since they basically dig deeper down the rabbit hole and end up making it hard for me back in my childhood days. Even to this day, I still have my trauma against teachers. I'm doing better but definitely not out of it either. I'm just putting a strong facade when interacting with 'em...
@monkey123 I don't know how much s--- you got back in school but I'm sure as hell any other kid would be at least terrified by that kind of s---. At least the least realistic thing about his situation was him not annoying people first to the abandon treatment he got since in this flashback I saw him as a happy-go-lucky yet lackadaisical kind of kid...