People are on <insert social network here> because their family & friends are. Once on, it's hard to un-glue because it keeps zucking you in.

Maybe. I joined fairly early, still have an account, but did become pretty disengaged from it after graduation. So maybe I didn’t get the proper gradual boiling experience.

I still have a Facebook account, and will occasionally log in (most recently attempting to sell something on their craigslist equivalent). The default content shown in your "feed" or dashboard is more than 50% engagement bait and/or slop. I attempted to start flagging those posts as "never show me again," but it soon became apparent that it was a Sisyphean task, and I just logged out again.