If I were one of these groups, I would consider suing the Supreme Court, and the leaker(s) individually (as Jane Does), and get discovery as to whether there was any coordination with outside groups in leaking the opinion. If there was intention to cause violence, and coordination with anyone remotely affiliated with the people causing the violence… I call that conspiracy.

Also, even if there wasn't, it was foreseeable that violence could happen. Negligence or recklessness would be the argument.