What I'd encourage you to do with that list is look at increments of 10 points and determine the caliber of QB in that group, generally.
Since the bottom player on the list has a score of 80, take a look at the caliber of QB you find, again generally, between 80 and 90. Do the same for 91 through 100, 101 through 110, and then 111 and above.
While I imagine you'll perceive a smattering here and there of QBs who "don't belong" in those groups, such as Jay Fielder's being near Warren Moon, I think you'll find that overall, in general, there's a darn good correspondence between the ordering of those QBs and the perceptions of their individual ability.
We're never going to find a "perfect" statistic. However, when you have one that's this strongly correlated with individual ability and with winning, you should probably be rooting for your quarterback to do well with regard to it.