"Leaders are obligated to respectfully challenge decisions when they disagree, even when doing so is uncomfortable or exhausting. Leaders have conviction and are tenacious. They do not compromise for the sake of social cohesion. Once a decision is determined, they commit wholly."

It's essentially saying fight for what you believe is right, but if the group decides an alternative approach don't sabotage the project from the inside because your ideas were not chosen just so you can say "A ha! Told you!"

I don't buy into most of the Amazon dogma (I currently work at Amazon). But I don't think the lesson behind this leadership principle is idiotic.