Is Violence Justifiable?

Violence is absolutely justifiable if it means gaining freedom from enslavement. I think what Johnson opposes in The Middle Passage is unnecessary violence for the purpose of revenge. As evidence, the Republic sinks after the Almusseri mercilessly kill nearly all of the crew needed to keep the ship afloat. The slave revolt relates to diametric forces and the balance needed to allow these forces to coexist in society. Violence is needed as a means of defense for one group to protect itself from being subdued by the other, but violence should never be used as a means to needlessly subdue another class or force them into slavery.