Honestly, I think it's OK to hold a bit of both beliefs and have that dissonance generate a sort of shame-tinged discomfort.
Violence should, by any rational and reasonable measure, be avoided. But that doesn't mean that violence isn't necessary at very specific points. To be more specific, the threat of violence can be a powerful equaliser when faced with aggressive, unrelenting abuse wrapped in denial.
We still shouldn't glorify it, though. Snitches get stitches in this not related to current events context, because a show of force is sometimes* necessary to establish the veracity of said threat. But we shouldn't forget that murder is murder, even when the murdered was a murderer.