Sure. I guess the point DHH wants to make is, that you better question the severity of the criticality of your mission. And he suggests that you do not directly couple the self-perceived value of your work to that severity. Because if you do so, there is no other way than declare your mission to be of “if we fail, the universe will implode”-critical.
If you could not follow that thought (no matter whether primarily agreeing or disagreeing), I suspect you are already endangered to be affected by the subject matter … ;)