This is the interesting question to me. I mean not one line or the other but the idea that both instances of "drawing the line" are just positions on the same spectrum. If you imagine a continuum of societal scenarios from blissful idyllic peace to total dystopian chaos, on the one end murdering someone as a mechanism for accomplishing something is clearly unwarranted, and on the other end it's pretty clearly warranted. So the question is where are we on that continuum and where would we have to be to justify this?
In my view when police are kidnapping people off the streets for expressing political viewpoints, when government power is nakedly being used to benefit the individuals wielding it, and so on, we're moving pretty quickly towards a situation where there's not much rational basis for believing the system will hold wrongdoers accountable. That's setting aside the fact that the wrongdoing by the health insurance industry has been going on for decades with little accountability.
I wouldn't say we're at the point where a killing like this is justified, but we're a lot closer than we were a year ago.
The particularly frustrating and worrisome bit is that there are obvious moves forward that I think would greatly reduce the likelihood (and perceived acceptability) of vigilantism, but the people in power are unwilling to make those moves. These are things like passing laws to make large swaths of current health industry behavior illegal, with specific penalties against executives, board members, large shareholders, and others who profit from the bad acts, and then rushing in to prosecute and imprison those people and confiscate the majority of their wealth. No more mister nice guy, no more dithering, just direct, forceful, unstinting action against everyone who has gotten rich off other people's suffering --- but doing it via the mechanism of law and justice to demonstrate that it is an implementation of the will of the people. That would make people feel like the system is working. But when those in government are unwilling to do that, it makes people feel like those in government would rather have the occasional vigilante killing, and that they are on the side of the executives rather than everybody else --- and that in turn makes a small minority of people more willing to give those officials what they asked for.