I am more circumspect that this is any different than communications before. Excess time spent on anything can be detrimental to ones mental health. As to the algorithms, the motion picture industry, politics, law, etc. all have learned to do research in how to make their products more successful/inviting and apply that research. For 2 generations the movie industry tests their products in front of audiences and then goes back to editing to make changes that they hope will make their product more successful. Other projects are just scrapped and never released based on what they found. Politicians test the words they use and the themes they push long before it hits their stump speeches. Lawyers test their cases in front of mock jurors before they hit a trial with it. Print media was a little behind the times in this, and as a result are finding their products becoming obsolete.
How is facebook any different?
People want to blame. If there are bad outcomes, there has to be someone/something to blame. I'm old enough to remember when excessive TV watching was causing all the problems with youth. Then gaming. Now social media.
What happened to all those folks watching a lot of TV. Now they produce the most diverse portfolio of entertainment imaginable. And those gamers? Created some of the biggest, most profitable companies in the world. (ever know an engineer that didn't game?)
Things people do aren't all good or all bad. They produce both good and bad outcomes. Entertainment is just that. It comes in all forms. The digital world isn't all bad...........although my preference is for the natural world. Mental illness comes from various points, both biological and the cultural environment or more likely the intersection of both.