There is a “disconnect between the severity of the crime and the gleeful savagery of the punishment.”

I think that puts it quite nicely. There's no problem with "social justice" as long as the response is proportionate to the offence committed. But the problem is so many get caught up in self-righteousness, which I think the is the most powerful emotion, and end up causing far more damage through their "justice" than the actual injustice caused in the first place. And thus the cycle of abuse is perpetuated.