I understand the argument that people should be able to manage themselves but human nature is not that simple. People are never told that they are about to use a drug that has been proven to have addictive effects.
Receiving a like on facebook releases dopamine the same way smoking, drinking alcohol or gambling do. All fine in the right amount but dangerous when taken beyond a certain point. One of the problems for example is that people tend to use these substances more under stressful situation like studying for exams, dealing with a problem in your relationship, etc.