I think that Steve notes an important consideration that is additional to all the qualifiers of Christopher in the OP: the question of whether one is acting as a private person (and thus defending loved ones and oneself) or whether one is acting in the office of, say, minister, in which one, as an ambassador of Christ, determines to act in the way that Steve did.
At any rate, we should always seek to de-escalate a situation if possible (we are called to be peacemakers), turning the other cheek and doing the sorts of things commanded in the Sermon on the Mount. In other words, we should never repay evil for evil, returning insult for insult, that devolves to fisticuffs or more serious violence. Yes, we may defend ourselves and there are situations--home invasion, for example--in which we should be as savvy and wise about it as possible. But most of us, in most of our lives, do not encounter lethal force, but more likely encounter the kind of thing that we should not seek to meet in kind but rather dial back--a soft answer turneth away wrath. We have to be careful to not let our mindset of "we can meet lethal force with lethal force" influence our much less deadly encounters and prompt us to seek to "hold our ground" with our friends and colleagues by returning unkindness for unkindness, insult for insult. That is quite contrary to the spirit of the gospel and Steve is to be commended for his Christ-like way of handling a situation that he assessed as a minor kerfuffle and not one involving lethal force.
Peace,
Alan