i think we should not look at the end of the spectrum and conclude stuff for everyone...
maybe there is a ton of people who will not get negatively effected by social media, as well people who will smoke a cigarette every 3 months in a party
As with everything there are winners and losers. Some built careers and companies by leveraging social media. That's in the pros column.
When I drill down into it, I think the potency is what draws me in. I sometimes feel this way on HN. "Let me check the comments". But FB, reddit, et al. are high octane versions.