That is not a dislike button. For example, you can select angry and it leaves it up to interpretation what you are angry about. Either way, most people think it is about the article you are sharing.

Here is an example: Share a post about Black Lives causing a riot.

Clear this is fake. Now if a reader of that post puts angry. Are they indicating the post is fake and they are angry with the original poster? Or are they now angry with Black Lives Matter because they think they caused a riot?

Facebook designed it this way so that the original author of the post still gets positive feedback. There is no need to change his/her behavior. They keep posting and the engagement for Facebook keeps rolling.