Its an update of an old custom
Willie Sutton,, a notorious bank robber from the 1920s, was asked once "Why do you rob banks?". His answer was both insightful and obvious -- "Its where the money is".
Robbing banks just isn't that lucrative these days. What is particularly lucrative is finding a group that you can get to sue a tech company or similar. It, too, is where the money appears to be (although most of their notional value is in inflated stock valuations). So everyone and their dog's at it. It doesn't matter if the plaintiffs are people alleging discrimination in a Tesla factory or a bunch of educators claiming that social media is destroying the children's lives. It really doesn't matter who, when or what because anyone who has been unwittingly been made party to a class action lawsuit knows that the only real winners are the lawyers.
FWIW -- I regard social media as this century's version of television. Its one of those technologies that was initially seen as uplifting, helping us towards an enlightened utopia, but rapidly became mostly a crock of evil. (There's no money in enlightenment.) (Also -- there's nothing like a parade of pensioners remembering how some sexual encounter (or even not-so-sexual encounter) in their teens led them to a life of trauma and despair (assuming that the person who did it to them is rich enough to bother suing, of course.)