It just seems like a very strange way to assign the groups. It seems logical to me that the more posts you have the higher rank you should receive. I mean you receive more stars, so it would make sense to obtain a higher, more prestigious title.
Eh... Most members of the blogs will never get much more than 1000 posts, so we give everybody a chance to be one of the current players. When people post enough to get their first star, they're rewarded with a Celtic superstar (Paul Pierce), rather than a role player. It's the system that has been in place for several years now, and I don't think we'll change it.
If it makes you feel better, think about it as two separate lists, one for 0 through 1000, and another for 2000 through 33,000.