I read that but i see it unfair, good luck with your bounty.
I think it's much more difficult to decide who should have how much. If we started doing that, then people would really get pissed off I belive. This way, no one has to feel like their contribution is being downrated since everyone gets an equal share without any thought behind it except what's the most simple approach.
Plus it's free money. None of the contributors have asked for this. Think of it as another way to give these guys a free beer after a hard days work coding