Curious, so, from a pure evolution and natural selection perspective ... how have pacifists survived?
They have an army protecting them. Or a society that has an armed populace. History is filled with armed groups killing unarmed, peace protestors or pacifists. One of the most extreme examples was the Hutus killing their own peace-filled Hutu people. The Hutu military threatened Hutu civilians that if they did not kill Tutsi, then they (Hutu civilians) would be shot and killed. And they did carry out their threats.
Evolution and natural selection have nothing to do with pacifists. Society does. Apples and Airplanes.