Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General Suggestions need a downvote option too

As far as I'm aware of, Uservoice doesn't allow downvoting. What you can do, though, is create an opposite thread and upvote that. So if there's a thread that says "put kittens in the game", you can create a thread that says "don't put kittens in the game".