Most of these ills existed long before Facebook. Facebook just makes it more apparent. Common people are on twitter, on reddit, on all the big networking sites directly pointing out that "everything is far from okay" and for a certain segment of the successful population of the world, they almost take that as an insult to them personally, because they're doing well and they assumed everyone else was too.
The reality is there are huge segments of the global and even American population that are being largely left behind by our new shiny future.
Secondly there are additional items that are necessary for this next generation that I don't believe are really accounted for. A lack of good internet access in the form of a smartphone or pc is a literal handicap, if someone can't justify affording that, I would very much consider them impoverished. Time is literal money and denying the most advanced tool in our day and age that will save you large amounts of time/money is poor from my perspective.
Yes I realize this measures something else, but it is rather opaque, and it fails to account for other things like debt.
The result is that that there are a lot of people who are officially in the government's eyes "above the poverty line" but who in reality can barely pay rent and afford groceries.
At my current job I work really hard, but I feel incredibly lucky that what I do is valued such that I am able to put about $3k per month extra money into a Vanguard mutual fund that has about 7% return. This money will continue to accumulate and grow with compound interest. I literally get more free money for already having money. That is privilege.
Meanwhile for many other people it's the exact opposite. They work equally hard (arguably perhaps even harder than I do) but the work they do isn't valued so they get paid almost nothing. After they pay their bills they don't have any extra money to invest. In fact they might have a small shortfall which over time turns into credit card debt. Now their net worth is compounding in the opposite direction.... down instead of up.
Someone in the second group has every right to feel depressed. I'd argue they probably even have every right to be mad as hell. They say that depression is just anger internalized. Some people are reacting to their situation by getting angry at the billionaires and super rich in our society. Others are experiencing that internalized anger that turns into depression that causes them to suicide slowly with drugs or alcohol.
Social media is bad, but it's not the cause. Our society is seriously suffering, and the gap between those of us who are privileged and those of us who have nothing is just getting wider.