I've been thinking about this question quite a bit lately,
and I know that the answer varies greatly from person to person. On one extreme you have people who don't feel a need to justify violence, and on the other extreme, people who think violence cannot be justified.
I myself think that violence, like hierarchy, must meet a burden of proof to be considered justified, and that is if it is social violence, if Noncombatants are left unharmed, and if said noncombatants are proletariat. If it does not meet all three, than I don't think it's justified.
Now that My stance on the matter is out of the way, what's yours?