It's not the contest rules, it's the voters. We each vote for our own reasons.
Some people vote for a grower they like - many people are at least swayed that direction. Other voters insist on good photography ...
I'm surprised at how many times I haven't voted for one of the two top results.
This is what I was really trying to say by popularity contest but you said it much better. It's just human nature to vote for a grower you follow / know / who has helped you. Add in that most of these entries are all great and its close competition makes it even easier to be swayed to the grower you know. If it was anonymous you could greatly cut down on that factor but i'm not sure thats a positive thing either. I personally think the amount of contribution people make to this community should be able to be considered. Lets face it the "popular people" are popular because they are very active and help a lot of others