I think you're using the word "stupidity" a little too loosely here. Going out and getting hammered to the point that you're staggering home, throwing up on the sidewalk, is stupid. Giving somebody a physical beating, with no morally or legally cognizable justification, is something well beyond stupid, is not something that most teenagers or twenty-somethings do, and should not be regarded as some boys-will-be-boys rite of passage. I'm not asserting that's what happened here, I don't know what happened here. But that's the allegation, and if it's true, it's not merely "stupid", it's reprehensible.
Sometimes criminal complaints aren't brought for reasons other than lack of evidence, and it remains to be seen whether criminal charges will be brought here. Regardless, I think you're being overly generous by essentially universally (or perhaps not so universally) equating lack of a criminal conviction with actual innocence. But bear in mind that the evidentiary standard is much lower in a civil trial than it is in a criminal trial. Even if criminal charges aren't brought, but Berry loses a civil trial for tortious battery, I think that would at least lend credence to the opinion that those in a position to do so may need to rethink his participation in the program.