The authenticity of those messages is not a given. Keep in mind, that's the task force that had multiple agents independently of one another steal thousands of BTC and launder the cash.
That whole investigation was shady as hell even outside of the agents who were corrupt and got caught. Keep in mind, those agents were the professionals looking for criminals doing that kind of thing. They of all people should have been good at stealing those coins and not getting caught. How many of them succeeded and weren't caught?
Also if the murder for hire allegations were legitimate, why was the task force even attempting that sting in the first place? The corrupt agent was the one who allegedly persuaded Ross to order the hit in the first place while he was simultaneously the guy who had stolen the BTC to begin with. That's textbook entrapment and I can't imagine that a DEA agent of all people would believe for a second that that would ever have a chance at standing up to scrutiny in a court.
The prosecution also knew about the corrupt agent who was behind much of the work on the case before the trial but at the time that wasn't public knowledge. They illegally withheld that information from the defense. Not to mention that the prosecution lied about how they identified the IP address of the Silk Road servers in the first place.
https://www.schneier.com/blog/archives/2014/10/how_did_the_f...
Looking at that traffic log, I'd wager that half of the people on this site are knowledgeable enough to realize that the prosecution committed perjury. Parallel construction is unethical enough as it is, this isn't that. They flat out lied about how they identified the server.
I think Ross certainly deserves a great deal of jail time for his crimes but that trial was a travesty of justice.