Hitler wasn't shameable, nor Stalin. America wasn't in fighting the native tribes in the 19th century, or the Philippines at the turn of the 20th. The Japanese at Nanking and elsewhere. The Ottoman Empire in Armenia (a matter Turkey to this day will not acknowledge or discuss), in Greece, in Assyria, and Kurdistan following WWI. China in Tibet. Britain/Australia and the aboriginal populations.
Guatamala (1968-96). Pakistan (1971). Burundi (1972 & 1993). North Korea. Equatorial Guinea. Indonesian in East Timor. Agentina (1976-1983). Rwanda. Cambodia.
Nonviolence is a tool. It's not the only tool. It is frequently, but not always, disproportionately successful.