Iran (1953) - overthrow of the Shah by the CIA
Guatemala (1954) - overthrow of an elected government on behalf of US corporate interests
Cuba (1961) - invaded Cuba via proxy forces, attempted to assassinate Castro (Bay of Pigs)
Vietnam, Laos, Cambodia (1955–1975)
Chile (1973) – overthrow of Salvador Allende
Nicaragua (1980s) - overthrow the Sandinista government (Contra war) without international authorization
Panama (1989) - invaded and overthrew the government without international without international authorizationauthorization
Iraq (2003) - invaded and overthrew the government without international authorization
Serbia (1999) - airstrikes without international authorization
Libya (2011) - exceeded authorization by UN to effect regime change
Syria (2014–present) - US military occupation and oil seizure is ongoing
There are many more, these are the more notable ones
That was never controversial. What was controversial was the unstated implication after that statement: "and people don't think they do". When your slogan is a false accusation against people in general, they aren't going to take it well. Approximately zero people in the US think black lives don't matter, so they aren't going to appreciate you coming at them with that accusation even if it is left unstated.
Which has prevented another world war, but not regional conflicts, a cold war, and whatever the history books decide to call the current social media driven conflict.
For just one example, see his response to the Massacre of Jallianwalla Bagh, which happened around the time of the end of WWI.
https://www.mkgandhi.org/storyofg/chap18.php
Non-violence formed a backbone of the Indian independence movement until independence was achieved at the close of WWII in 1947.