As far as ignorance is concerned, not just Buddhism, every religion recognizes it as the source of suffering.
Dalai LamaOne Mongolian leader became a very, very brutal dictator and eventually became a murderer. Previously, he was a monk, and then he became a revolutionary. Under the influence of his new ideology, he actually killed his own teacher. Pol Pot's family background was Buddhist. Whether he himself was a Buddhist at a young age, I don't know. Even Chairman Mao's family background was Buddhist. So one day, if the Dalai Lama becomes a mass murderer, he will become the most deadly of mass murderers.
Dalai LamaFrom the scientific view, the theory of karma may be a metaphysical assumption -- but it is no more so than the assumption that all of life is material and originated out of pure chance
Dalai LamaIf you wish to experience peace, provide peace for another. If you wish to know that you are safe, cause another to know that they are safe. If you wish to better understand seemingly incomprehensible things, help another to better understand. If you wish to heal your own sadness or anger, seek to heal the sadness or anger of another.
Dalai Lama