Lama Ole’s answer:
Anger is the biggest enemy of our development. If one is angry, one destroys everything: the joy, the good feelings—everything.
Anger is actually a confession of weakness. At least this is how we see it in Scandinavia, my home. If you become angry, you have already failed. It means you couldn’t handle the situation.
But this doesn’t mean that one shouldn’t act powerfully! Powerful action is important; but one must not be angry in the process. One can do all kinds of things as long as the motivation is to bring the least possible amount of suffering into the world. With this motivation, one can even become a soldier as a Buddhist. I would also take drastic measures if someone got in the way of a good cause; but it would be without anger. It is all about the feeling one has while doing something. A doctor who doesn’t operate on a patient because it causes pain is not a good doctor.