They don't care much about security (evident by the recent twitter hack). They don't care much about privacy. They don't care much about functionality.
Increasingly, I don't think people even care about the content or relationship/social aspect of the social media. My dad has like maximum number of friends on Facebook and I really doubt he actually engages with them. His feed is full of bullshit that he sometimes tell me about and is even self aware of a lot.
Why do you use facebook despite that?
He doesn't have an answer. I fear he is just addicted to scrolling when he has nothing to do.
He is also using Facebook and whatsapp because of peer pressure.
A weird phenomenon in india is how easily bullshit spreads on whatsapp. The reason is most people forward without even consuming the content. It's almost like they are getting rewarded for a completely different thing than the intended or well communicative purpose of the medium.
I suspect they find the engagement sufficient. They forward and someone comments. The dinging of the phone itself is exciting.