Well, a measured quantity of violence ('violence' being a very broad category) targeted at someone who is clearly causing harm is sometimes the only effective way of stopping a greater amount of harm. No-violence is clearly better, but assuming that (say) a rape is being committed, some degree of violence is a reasonable response to stop things from happening or deter other things.

You are right. Casual threats of violence get me about as riled up as casual sexism so this was both a perfect storm and an overreaction on my part. I should have silently grumbled and ignored it.