I don't see it as a "need", I rather see it as something that comes by itself, even if nobody interferes and lets people do whatever they want. They are always going to elect a leader among themselves, if not one overtakes the task by himself without telling him (but with those you're already quickly at those which in the core point have evil intentions).
Depending on how humans individually are shaped throughout their life, they change into a passive position then and let their leader do whatever he wants or not.
In order to prevent circumstances like the world has now, you need to apply structural measures and means which force the mass of the faithful sheep to take care about what their leader does and measures and means that they actually can effectively do this. So to say: If you do a lot of shit as a leader, then you are quickly to be gone from your position, quicker than you can see.

The question of evil within humans is a different matter, but I'd find it too big to discuss it right now in addition to this subject.