I know that some people are up there, simply because their accounts are really big. It's why I did not unfollow anyone I actually appreciate, because in their cases, I really don't mind that they show up in this list. I know they do a lot for the community and don't abuse their VP by only upvoting themselves.
The only real way to solve most of this is by getting rid of self-voting. However, the biggest abusers will just continue doing so by using an alt account...
... and that is precisely where the discussion must go over time; To how we can introduce better solutions against sybil/sockpuppets/alternate accounts.