You nailed it - wherever people can dislike, downvote etc. there will eventually be a lot of flaming, mobbing and other bad behaviour that discourages people from using that website. We have a forum where you can like and dislike posts and some people actually spend a lot of time disliking posts by people they don't like systematically (up to 50/day are allowed). We're now considering a very low limit for dislikes/day ...