Because, when I don't know what to do for 5 minutes, there is super high chance I will figure it out within reasonable time still.

Giving up after 5 minutes of not knowing what to do is absurd.

> Most people find that feeling of helplessness demotivating and stressful which is why I created the rule.

Your rule is making people helpless, it makes them think slight stuck means they can't do it. So they will forget how to solve problems and will end up limited to do only simple straightforward tasks.