OR...ANY frickin' way in which you can put this without making an absolute statement.
Yep. In fact, the only objective "we can point to it in the rules" thing on this topic is that the DM should be an objective referee, not favoring PC death nor avoiding it. The only thing remotely close is in AD&D where it says that if the PCs die from their own poor decisions or bad rolls, too bad for them, but if they die from something completely out of their control and they didn't stand a chance through no fault of their own, then you can make a call.
But in general, saying that a DM's job is to avoid killing the party is objectively wrong from what we do see in the books, and at the very least is a subjective preference of the individual only. Speaking for myself, I would not want to play a game where the DM fudges rolls or changes things to where my PC has no real risk of death or disfigurement. Might as well just sit in a circle and share story time if that's the case.