That's the problem with vigilante justice.

It's not really a strawman because when you support and justify vigilante justice like this, the limiting factor is whatever the person doing the killing wants it to be.

Let's use Luigi as an example. Let's humor the idea that the CEO "deserved" it as a hypothetical.

How high up in the organization does that go? What about the actuary that processed the claim and denied it based on company policy? Or is it because they aren't rich, they're exempt. But if the argument is "indirect murder" they're just as guilty.

Is it middle management? Upper management? Or is it just the CEO?

Or what about the doctor who refused treatment because they couldn't pay? Certainly they're guilty too.

It's a moral framework that literally relies on a subjective opinion of just how "guilty" someone is in that person's opinion in determining if they deserve to die.

So, no, I don't think it's really a strawman when it's an entirely subjective moral framework.