Buddhists in Sri Lanka have engaged in mass repression against Hindus and Christians and Buddhists in Mongolia tried to wipe out any practice of tribal animist religions. Then there's these guys: http://tkb.org/Group.jsp?groupID=4263
So I vote Wicca.
There's also the guy from the Hells Angels who used to be one of the most feared and most powerful members who then converted to Buddhism while in jail and has since then been a "model inmate" who quite literally refuses to harm a fly.
Well the same is true of plenty of other inmates who converted to all sorts of other religions.
Just saying, even they don't have a perfect record. Lewis said something too about some people called the Bodhivasattas or whatever but I don't know anything about them.