Has the legality of these sorts of things ever been tested? I can easily imagine that the courts wouldn't actually stand for the idea that someone can throw away their right to sue by clicking on the bottom of a thirty-page ALL CAPS agreement.
I'm not even sure whether someone can waive their right to sue by signing a single sheet of paper labelled "Waiver of right to sue".
It's not a waiver of a right to sue, or any disclaimer of liability. It's an agreement not to be in a class action lawsuit. Some of them can also force you to use an independent arbiter instead of suing. But wither way, they can still be held accountable.
Forced arbitration clauses, with an arbiter of the companies choosing, are in no way "holding them accountable". They are pretty much the definition of an unjust kangaroo court.
I'm not even sure whether someone can waive their right to sue by signing a single sheet of paper labelled "Waiver of right to sue".