alt Hacker News> So do we now roll back all of the previous copyright cases where downloading music with bittorrent has been prosecuted
No, because those cases were pirating-while-poor. This is pirating-while-trillion-dollar-corporation, which falls under a completely different section of the law.
At this stage, you are going to far in claiming that. So far, all that happened is that Meta's lawyers claimed it was fair use. They are paid to try every argument they can think of that might work. Just because they make the argument doesn't mean the court will find it has any merit.