But that's not really a position that has basis in reality. To those doing the harassing, getting the people they target off of social media is, for them, a win.
"My point I suppose (assuming I even have one) is why they would feel the need to stay, rather than just leaving."
Because they want to use FB and social media like everyone else is able to?
"It didn't impact my life at all to delete my account"
I'm glad for you, but you're not everyone.
"and I'm asking whether there were some development since that makes one NEED to stay"
NEED doesn't come into it at all. If they want to continue to use the platform, they should be able to without dealing with that kind of harassment, plain and simple.
"but the question I asked, and think they should be asking themselves is "why?""
And I think you should ask yourself why that question has any bearing on the situation. Why they should have to consider whether they can continue to do the same things that most other members of society get to do.