Violence and nonviolence, in the face of violent, intolerant ideologies such as Nazism, or even colonoalism, is not as clear cut as it gets made out to be. I think primary arguments for violence are often misunderstood and taken out of context.

I don't think it's a moral question, as moral reasoning seems to lead to either 1. Violence is always wrong or 2. Violence is a moral imperative against certain enemies, for to do nothing is to permit and assent to the violence that they inflict. Neither of these absolutes are adequate within actual consequences, although both views definitely have to their credit historical circumstances where these strategies were arguably successful and progressive.

However i think there are important lessons on violence and nonviolence that can be learned from various historic examples:

1. Individual violence against individuals does not advance progressive goals. Individual violence merely strengthens the status quo against that violence, and can be used to justify mass violence of the state or militias against masses of people, usually a targeted minority.

2. Nonviolence tactics can be effective against state or military repression, but state and military roles in genocidal campaigns, or participation in extrajudicial violence shows that otherizing is effective at dehumanizing, and in order to be effective must consciously and effectively humanize the nonviolent activists to the oppressing forces in order to introduce contradictions into their justifications and create splits within the ruling classes of the oppressing powers. This is a long term strategy so you have to make sure that whoever you are nonviolent resisting isn't gonna just kill everyone, which they will try to do, even if it is against their interests to do so.

3. Violence may be immediately necessary to protect human life, in the short term or in the long term. The fact is violent repression creates the conditions for violent resistance escalation of violence sharpens the contradictions already present in the status quo and creates splits among the various classes in an oppressor/oppressed dialectic. In this way violent resistance can galvanize both violent and nonviolent forms of resistance for your side, but it also does so for the other side. Therefore violence should be avoided if possible, but if violence is perceived as defensive or necessary it can have progressive or even revolutionary consequences on consciousness and material conditions.

So the conditions that introduce struggle and violence are social contradictions, not necessarily a conscious choice by individuals intending to do violence, although sometimes it is.

So for my part, as an American with that perspective, I've become fond of the concept of "armed nonviolent defense." An example of this is the Deacons of Defense and Justice that proliferated in the south during desegregation. Groups of black men took up arms to defend their communities from Klan violence, and provided security for MLK, CORE; as well as forcing the Klan underground in the south for a generation or two. So organized citizens defending their communities and working together with political groups and revolutionaries to defend against violent reaction without the progressive political movement taking it upon itself to be a violent one.

This is an immense and complex topic and the rightness or wrongness of it is contingent on the historical conditions that are present. So understanding "correct" usages of violence and non violence doesn't extend from our moral obligations, but our obligations to the real world, each other and the future of our movements.