Is it taboo in America to talk about atheist violence?

[Thats my opinion]

117. There is a natural human proclivity which spirals down toward violence, revenge, conquest etc.

This proclivity is traditionally countered by ethical systems which grow out of some institutional rootage. Historically these systems are the product and core of religion. These institutions are the thin veneer over the jungle. You find a hunger for non-violence in all the major world religions: Christianity (as seen in Jesus) Buddhism, Islam, Judaism, Hinduism, etc.

It is true that believers in all of these systems often bastardize them and use them as an excuse for the very violence the systems are organized and promulgated to oppose. In those cultures with solid ethical norms growing from a religion basis, others, who are not part of the religion, often are attracted by the non-violent posture and adopt that ethic while not adopting the religion. So the religion has an impact far beyond its own borders. Nevertheless both among the religious and non-religious, without some institutionalized ethical system it is easy to turn to violence, revenge, conquest and all the rest. Where else do to these noble norms come from? Certainly not from human nature.

Therefore, while it is fair to say, "With God anything anything is possible," it is also fair to say, "Without God anything is possible."