Sure. Leftist violence against other leftists is well documented.

https://en.wikipedia.org/wiki/Left-wing_uprisings_against_th...

Usually one of the first thing that communists do once they are in power is crush the anarchists, and other competing leftist movements.

None of this is controversial.

Soviet repression of gay people was also well documented, as well as Cuban repression/murder of it's gay population.

https://www.thedailybeast.com/fidel-castros-horrific-record-...