I feel that some of our users have taken the change in norms with subjective questions too far.
This comment is the last straw.
Any actual experience with allowing players to vote what can or cannot be killed? – {Mołot 22 mins ago}
It reflects a complete misunderstanding of the answer, and it misrepresents the text of the question in terms of addressing the actual problem. A GM and all of the other players see the game one way, and one player is trying to do something different that the other players do not agree with.
The problem in the question header, about "killing the unkillable," isn't the issue that needs to be solved. We have X-Y problem questions arise with some frequency. The problem is (1) getting the other player to stop being disruptive and (2) the GM's frustration with the same. As I see it, a GM needing to learn how to say No and to stick to their decision (and to apply basic small group consensus building) is what's at stake. And that snarky comment gets added under the answer that addresses the X-Y problem. I just discovered that the answer was accepted by the person asking the question - this lends support to my point that the text of the question lays out the problem, not the title. I now discover, a day later, that the querent changed their mind and chose another answer.
At some point, before deciding to throw that "Do you have expereience with {X}?" line out, I ask anyone pondering such a comment to think first, read the whole question, sum up the whole problem, and then look at the solution being offered to the problem.
I am not convinced that all of our users are going through that process before raising that objection in the past few months. (Though some certainly are).