Why are Buddhist people able to cause violence?

There's been persecution of ethnic minorities in Myanmar. Some monks in Myanmar align themselves with groups that cause violent clashes. There has been a civil war in Sri Lanka where Tamils felt the need to stand up to purported oppression by the sinhalese, an ethnic group that adheres mostly to Buddhism. In response, sinhalese that forced Tamils to strip naked in a show of dominance, dehumanizing the victim, felt supported by the sinhalese government. In at least once instance, the victim was killed afterwards. How is this possible? Do buddhists find encouragement of violent action in the suttas? If so, where?