When you don't have Facebook your friends and family just txt or email. I mean Facebook book hasn't even been around that long. To pretend it is something like water or electricity is just preposterous.
Data point: In 2009, the admin assistant in my department at university told me she's been getting quite a few upset incoming freshmen because of the requirement to have an email address for university classes - many of them had never used email before, and had communicated only via text, and IM apps. This was over 10 years ago.
Also, I'm surprised the university wasn't assigning them .edu emails anyway. My younger brother is in college now and he loves the school email for getting student discounts.
I'm not saying all those who complained did not have email - likely many/most did. They didn't like being required to use it. However, there were quite a few who claimed they had never used email. I suspect that they likely had, but only for a few formal things (university applications, etc) - something they used perhaps once every few months. They probably didn't like the idea they'd have to check their emails so frequently.
There is also a huge difference between people making the decision to stop using social networking, and being suddenly and unexpectedly cut off from a support network. The former can have positive effects on mental health, the latter will certainly not.
I say this as somebody who deleted their Facebook account over a decade ago.