In a case where "harboring resentment" concretely means "not going to his high school reunion with people who committed violence against him".
Most children of abusive parents still harbor resentment, even if they become healthy enough to move past it in their everyday life. You're expecting someone who was surrounded by an abusive peer group (and an utterly apathetic group of adult "supervisors", who are all but guilty of criminal neglect) not to have negative feelings about his experiences when his former tormenters invite him to a reunion?
There's not going to the reunion, and then there's posting fuck you's on the internet in a sad rant.
I'm not commenting on his decision to not going to the reunion, I'm commenting on the fact that he's still very upset by these events. It's in his interest to let it go, but I don't expect him to be best friends with all his bullies.
A victim of abuse--who has gotten over it and had a successful career--is upset at being reminded of his abuse. I'm not sure exactly why you're blaming him.
In fact, don't ever speak this way to an actual victim of abuse in person, ever. All you'd accomplish is encouraging them to repress their pain and feel guilty over it. People heal in their own time.
I didn't accuse you of confronting him, I'm just warning you not to confront anyone. Criticizing someone for being vocal about unpleasant events in their past and not healing fast enough doesn't help them heal, it just makes things worse (and makes it harder to heal by pushing the person into repression and denial). Frankly I think he seems to be doing just fine.
