A shit-post would be immune. There has to be a credible threat.
The courts decided this time there was. It's a bit weak in my opinion, but I can see the point.
It would have been reasonable to fear that someone would have tried to collect on his offer.
He was known for being wealthy, unscrupulous, and a drama whore.
It is not reasonable to take your shit-posting seriously, though.
So if I made a post asking for a lock of @innocentbystander 's hair, it's totally fine, but if a public figure does it then jail?
No. If you made a credible attempt to cause an assault, you would be at risk of criminal charges.
You can say anything you want. But if you start inciting action, especially violence, you risk culpability.
Shkreli made a shitpost and got his bail revoked because of it. I post some stupid god damn shit online, and if you take many of my posts out of context, then I should probably spend a life sentence in prison, right?