I honestly don't see the point in a negative rating and I guess any ratings in general. If you dislike something that some says simply click that little grey box at the bottom of the page and explain why. Especially with things like suggestions. If I suggest something and another user disagrees and simply pushes a button or posts "-1" that holds no value in explaining what they thought was wrong or needed changing. If you really have something to say about someone else's post, why not just say it?
I honestly think we should remove all ratings besides like and dislike. Everything else is unnecessary in my opinion
I think a rating "disagree" could cause conflict or can be used unnecessarily. I do not believe that this is needed.