A Marxist who does not engage in violence is a non-violent Marxist, by definition. Don’t fall into the Cold War trap of assuming that communism means violence and evil, and capitalism means peace and prosperity. Good and evil people can be found on both sides in most wars.
I’m not disputing that terrorism is bad. My original point was simply that the ANC, during its early years, did not engage in interpersonal violence, and that this is (in my opinion) a thoughtful and reasonable way to conduct an uprising that seeks to make a point without losing the moral high ground. Their early acts of sabotage, the ones that got them thrown into prison, were against unoccupied buildings at night, aiming for maximum property damage with minimal loss of life. If I wanted to conduct an uprising, that is how I would do it, too.
Later, they became violent and terroristic in the traditional sense. But that’s tangential to the point I was making.