Unfortunately, the combined might of General Franco and his fascist allies from Germany and Italy were too much for the meagre ranks of anarchists to contend with. Even during the Russian Revolution, anarchists were present, but could not gain any large degree of acceptance. The Great Purges saw to that. The belief the anarchists held could not even begin to defy the fear which had been instilled in the people. All this in the name of a man who wanted peace.
Revolutionary anarchists hold violence to be a necessity in achieving their utopian state.
The only way to make the ruling class take note is with a few well placed bombs. If the anarchists can show the world that they can not be easily stopped, then perhaps, useful change can be brought about. The only way to put a bar in the way of the power of the ruling class, is to destroy it. Propaganda of the deed emphasizes action, rather than threats or just talking. If change is to occur, change must be drastic.