Peace activists are often accused of being naíve dreamers when it comes to dealing with conflict or dangerous enemies.
So what is the alternative? Usually it's to fight fire with fire (i.e., revenge and retaliation).
The very nature of peacemaking, however, is not to fight but rather to confront "the opponent" with intelligence, craftiness, humor and a thirst for justice. We have some splendid examples of this approach in Gandhi, Martin Luther King, Jr., Dorothy Day, just to name a few. Skeptics recoil and sputter that such people were exceptions.