I'm a little confused - is this a judge-based jam or a community vote jam? The overview says it's judge-based, but atm it seems like anyone can vote.

In my experience, there is always community voting.
Yet, it is up to jam's admins to designed winners of jam, based on their own critiques.
Rules of this jam say "the judges will gather to determine the winners", so it's up to them in the end.

Collision Check is correct, everyone is free to vote on the jam entries but we are meeting with the judges to designate award winners!