I have a co-worker who never stands up for himself nor does he even politely confront those who are giving him a hard time. Instead, he gets angry (away from those with whom he is in conflict). Sometimes that anger comes out toward me. He can occasionally bang his fist into the top of his desk. Do you think his actions are sufficient to relieve his anger or does this even help at all?
Your co-worker seems to be using the psychological defense of displacement, which means to take out the anger on something or someone else rather than on the original person who acted unfairly. In the short-run your co-worker might experience some relief from this catharsis, but in the long-run, as I am sure you know, his hitting the top of the desk will not solve the injustice. If your co-worker can do some forgiving and exercise this along with courage and a quest for justice, then he might be able to go to those at whom he is angry and talk it out in the hope of a fair resolution.