Zero tolerance exists when there is no common sense.
That’s because rigidly sticking to a policy is easier and requires less thought by management than using common sense. If management uses their own judgement and reasoning then they might get flack for a decision they make. Mindlessly implementing policy from above without question (zero tolerance) means they are covering their own backside at the expense of their people. Great leadership there. :-/ We routinely see the same thing with schools and their zero tolerance policies. That’s how you get kids suspended for cartoon pictures, poptart shapes, etc. Mindless drones CYA.