Catharsis, I've gathered. I know this is for me so it may seem strange when I said I don't exactly understand it either but it's the truth, a complicated one but the truth nonetheless.

Exercise doesn't really help in this case. From what I gather.. Breaking things is familiar, it's exertion of pent up energy and the satisfaction of not having to worry about holding back or staying completely regulated or bottled up. In a controlled space at least this allows that energy and anger to be released in a way that won't end up blowing over and hurting anyone.