I suspect that @curie will take a look at this post and comment and hopefully make a comment to explaining the voting pattern and for the post you have linked.
Saying that, if you were to do the same review of many of the top witnesses, I suspect you would see a much small vote spread.
well once they convince me that they are paying attention around here i will restore my vote. Not that my vote means anything but i feel it is better placed elsewhere or not at all for now.