I’ll push back on the premise and argue that often, the refutations are made because people want an excuse to justify their behaviors they know are wrong by setting up deliberately absurd premises. The arguments are less an attempt at getting at truth and more an attempt at feeling better about performing a moral failing they were going to perform anyway.
If you accept that Russia’s unjust invasion of Ukraine was “evil”, do Ukranians taking up arms and killing Russian soldiers count as an “evil”? Most people would argue not. But within the war literature, there’s a broad consensus that even in wars for a “just cause”, there are unjust acts: torture of captured soldiers, rape of civilian populations, weapons designed to maximize pain rather than achieve a war aim. And the justifications for why these things shouldn’t be done uniformly aren’t about the impact it has on the other side, but on the detrimental effects these things have on your own side. We see a fairly consistent strain across a broad sweep of military history over what is considered “moral” and “immoral” conduct during warfare where there might be disagreements over which actions precisely fall into which buckets but a consistent warning to avoid immoral conduct during war for purely instrumental reasons.
At the same time, we’ve seen over and over again, military leaders in the vein of Pete Hegseth who believe that all of these pesky rules of engagement are the reason why the military is losing and a “gloves off” approach is the genius insight to produce a winning military, using the exact same “we gotta do evil to those who do evil to us” arguments. So he’s bombing random boats in Central America and claiming they’re drug boats without verification and then deliberately killing the survivors so nobody can find out if their targeting is accurate or not and booting trans people out of the military etc. And the arguments against all this behavior isn’t that we should feel bad for drug dealers and go easy on them, but that it’s self-defeating.
You see this same strain in criminal justice thought: That we should have things like impartial trials, anti-corruption task forces in law enforcement, access to legal aid to the accused etc. and not fall into the easy seduction of mob justice or personal vendetta settling, not as a benefit of the “evildoers” in our society, but as a benefit for the rest of us. And the same arguments back of “well, yes, but this specific case deserves an exception because it’s a unique evil that deserves a unique evil response”.
I think it reduces down to two trivial resolutions: Either you designate certain behaviors as evil, ie: all killing is evil, in which case, it becomes trivial to concoct a hypothetical example where you 100% need to do an evil action in reaction to another evil action.
OR: You designate certain consequences as evil, in which case it becomes trivially true that it’s never right to do an evil action in response to an evil because if you can prove it was the right thing to do, then it definitionally is no longer evil.
But the special pleading for a 3rd response is because doing the right thing is hard and we don’t like to acknowledge our own moral failing so we try to feel better by arguing our case is a special exception to the rule.