Do you have a source for that extraordinary claim that Facebook was designed from the outset to make people unhappy, and that people use Facebook more when they are made unhappy?
https://www.upmc.com/media/news/lin-primack-sm-depression
"Social Media Use Associated With Depression Among U.S. Young Adults"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477910/
"There is increasing evidence that the Internet and social media can influence suicide-related behavior. "