It isn't terribly clear what the criteria are meant to correlate with -- the Wikipedia page explicitly says that it's not about habitability, but doesn't really say what it is about. Maybe the criteria and exponents have been arbitrarily chosen to "get the right answers" according to someone's intuitive notion of similarity.

It certainly seems strange that Venus is scores lower than Mars, too -- by any reasonable definition it's the more "Earth-like" of the two -- it has an atmosphere, it's closer in size and mass and so on. The weights on the surface temperature measure just kill it, though.