I think we're trudging into lawful stupid territory with that one.

Isn't this vote brigading and against the rules?

Not really, no.

Vote brigading is a massive, coordinated effort to manipulate another community by voting, usually with the intent to harass or subvert (aka everybody from /r/thedonald downvoting pro-choice comments on other subs). In order for something to be considered brigading, it should really run counter to the intentions of the affected community or contest.

All I see here are people voting for their preferred winners on a site built to allow people to vote on their preferred winners. Yikes brother.