I am the person who wrote the original material which Sundragon2021 used to kick off his post.
The material which Sundragon excerpted does not include the paragraphs in which I
answered the rhetorical question I had just asked. Instead, he simply expresses shock and dismay that the question I asked could even be posed.
This is the link to the full post.
You can go there and read, or just reread a short summation I'll put down here.
The way to ensure that character death occurs from 1) stupidity, 2) voluntary acceptance of risk, or 3) climactic battles is as follows:
Begin by making sure that the players can't be killed in a single roll during standard encounters. Allow them to instead be horribly wounded but not actually killed by a single roll, leaving them close to death but with the opportunity to react. Death looming over a character is better than being struck from full health all the way to dead in one shot.
Then, give the characters abilities and tactical options that let them react to precipitous danger. This can be as simple as a good method of running away, or as complex as a system of once a day abilities that the characters can use to amp up their power level.
Under my system, when the characters get nailed by a lucky critical, or a save-or-be-screwed effect, the character will be horribly wounded instead of outright killed. As a result, the players will have to change their strategy from "kill the monsters without expending more resources than we can afford," to "do everything it takes to save our ally and escape." And fortunately, they'll have tools to do so.
If they don't change their strategy, in spite of having the opportunity and the means to do so, then their deaths can be blamed on stupidity or on voluntarily accepted risk. Which are ok reasons for character death.
See the change in focus? The possibility of death is there. Screw up, and you can die. Take risks you know are bad ones, and you could die. Its just that now there are also
contingency plans available for avoiding that death.
And that's my take on the subject. Sorry you had to wait until page 2 of the thread to hear what started it.