Ignorance

Buddhist-Muslim riots in Myanmar are an example of the pollution of goodness by religion. A Buddhist rioter is not a Buddhist in the sense of following the teachings of Gautama, the man who is now referred to as Buddha. Buddhism, as originated, is a form of personal practice, not a religion. Intrinsic to that personal practice is nonviolence toward all living beings. 

The roots of religious hatred in Myanmar and much of Southeast Asia stems from the Mongol invasions of the 13th century which led to the destruction of an evolved Buddhist culture of monasteries and libraries. The Mongols, a culturally warlike people, incorporated Islam into their society as part of their earlier conquests of Muslim countries. They may well have been inspired by Muhammad's own military conquests. When the Mongols invaded, they practiced rampant murder of Buddhist monks and razing of all Buddhist institutions.

None of this history justifies the violence in Myanmar today. In the words of Gautama Buddha,

All beings tremble before violence
All fear death
All love life.

See yourself in others.
Then whom can you hurt?
What harm can you do?

He who seeks happiness
By hurting those who seek happiness
Will never find happiness.

Shambhala Pocket Dhammapada, Verse 10, p36