The dislike button should not be allowed.
First of all, it could hurt feelings. Many people could get offended if they get a large amount of dislikes.
Second of all, it's unuseful. How would most people use it? Maybe people might get jealous of eachother and start disliking eachothers projects. I know most people won't do that but that's just a thought!
Third of all, it has disbenefits. You might be mad at someone and dislike that person's projects and express your feelings which makes them pay attention to why they are mad, or you could really hurt someone's feelings.
These are just my opinions, please do NOT start a flame war. I think these are most of the reasons why the hopscotch team didn't put the dislike button as an option, good night for California!