I think intent matters and words matter. That he wrote and made threats, explicitly, is very much different than a person suggesting someone should be hanged. The intent was obviously and he rightfully spent three years in jail. The slippery slope is when we start making excuses and allowing behavior that is somehow excusable because it is on the Internet.
He was paraphrasing a song! It would be just like me saying, “And I’ll shoot a man in Reno89519, just to watch him die.”
(BTW - I was going to use that Johnny Cash analogy with your handle BEFORE I saw what your handle was! Spooky ...)