The Dahmer quotation is similar to what is embraced by Communism. The reason Communists can be so cruel and inhumane is because their "government" has atheism at its heart. Since without God there will be no consequences for inhuman behavior, why not kill your fellow man when they do not conform to your philosophy?
Just goes to show that an evolutionist doesn't necessarily and logically have to become a nazi or a communist; there are other options. He could become a cannibal. That should make all evolutionists feel a bit better about themselves.
In fact, there are a couple of other options. For instance, female evolutionists could become welfare mothers, you know, the thing about "he who dies with the most offspring wins"...