I think they mentioned something about this before... don't remember...

Anyways personally I think for user posts having a dislike button isn't a good idea, it can be abused in different ways but for Rep/Dev responses I think it's good thing to have. They said in the past the Like count will show how many people may agree since some don't like to post their comment and if they don't like it they will probably write why they dislike the idea, but when you think about that some people who may dislike don't want to post their thoughts too and if the devs release something those people didn't like it might disappoint those people.

At the same time though displaying number of dislike would also encourage some people who just don't care to vote for whichever they feel is right therefor for dislike if I was the forum mod/rep I would hide the total count, just make it so the dev/reps can see the total. This may lead to some people still think if the feature/content/changes get/doesn't get implemented to complain but it should help out some situations, after the discussion is over the dev/rep can show the results of like/dislike to prove that they followed what the majority of the forum community agreed on.