It may not be a dislike button, but is it similar?
Facebook is testing a new feature intended to flag questionable comments on public posts.
Tapping the “downvote” button will hide a comment for the user who tapped it and ask whether the comment was offensive, misleading, or off topic.
Facebook confirmed with the The Verge that the test of the feature is in progress.
According to The Verge, the downvote view counts are not visible to users. A Facebook spokesperson says the feature is intended for people to give feedback about comments on public page posts.
Testing of the downvote button is running for a small group of people in the U.S. only.