Per Vox, Facebook is going to add a “dislike” button soon, but it won’t be exactly what I thought:
By contrast, Facebook won’t treat a “dislike” as a vote to stop showing the post to other users. Rather, it provides a better option in cases where friends and family paste bad news, like a death in the family or a natural disaster. “What they really want is the ability to express empathy,” wrote Business Insider. “Not every moment is a good moment.”
If it is going to be designed this way then my assumption is that the user will be able to pick whether they want a Like or Dislike button attached to their update. If every post has both, then it will be very confusing it ’s purpose. I have long understood this predicament. If someone posts something “bad” you don’t really “Like” the post, but that is the only way to show support without posting a comment. But there are also times where you don’t agree with something someone has posted and then you are forced to comment. Maybe that is how it should be to not encourage negative comments, I don’t know.
The only thing I do know is that if Facebook adds this future and includes both Like and Dislike on every post, it will not work the way they want it to.