If there was some action that happened that made them all independently realize their liability, forcing them to act in similar matters, then it need not be col

If there was some action that happened that made them all independently realize their liability, forcing them to act in similar matters, then it need not be collusion. Users have no more legal right to act on these platforms against TOS than I do to camp on our property. And, since there are plenty of other hosts and platforms besides these few, it will incredibly difficult to claim anti-trust.