Why Are Buddhist Monks Attacking Muslims?

Aren't Buddhist monks, indeed all Buddhists, supposed to be non-violent?  In Burma and Sri Lanka, they are spewing hate and joining mobs.

This  great BBC article explains the trouble. In Sri Lanka, according to the BBC, the issue or flash point is the halal slaughter of animals. That has led to boycotts of Muslim businesses in Sri Lanka.  Fortunately, there has been no violence yet.  But in Burma, the situation is different. A somewhat crazy Buddhist monk, Ashin Wirathu, who refers to himself as a  Burmese Bin Laden, incites religious hatred.

"Aren't the Buddhists supposed to be the good guys of religion?"  The BBC traces the history of Buddhist aggression and attempts to place it in context with the other major religions.