Should the user be able to program every memory timing option, even if by doing so they introduce occasional crashes? Should they be able to set every thermal threshold, even if by doing so they're reducing their hardware life expectancy?

Uh, yes?
"Hell yes", even?
It's the user's bloody machine. They have every right to smash it with a sledgehammer, should they desire.

Making a conscious decision to trade off a small amount of life expectancy for the ability to use it the way they want to during that life? Why would you even question that?