He wasn't charged with it and the indictment was dismissed with prejudice after the failed Supreme Court appeal. He was however sentenced as if he was convicted of that, the judge explicitly stated as much during the sentencing, and the prosecutors also used that to sway the jury even though they wouldn't charge him with it.

Part of the reason why is because those charges most likely would not have actually resulted in conviction because it was blatantly entrapment on the face and the veracity of those claims is dubious given that all of that evidence is coming from Carl Mark Force IV, the same agent who is now convicted himself for his corruption in that investigation and stealing a fortune from the Silk Road and just pocketing it.

I realize it may seem like an entrapment defence wouldn't apply here but keep in mind, even for the government's alleged chain of events, the government absolutely induced the crime, they stole the money, they came along with the "solution", etc. Then there's the matter of if DPR was predisposed to commit the crime. He certainly had a predisposition to commit crime, but definitely not murder-for-hire in particular. Even in the conversation with Carl Mark Force IV, he did not want to kill him and explicitly stated so, the special agent convinced him that killing him was his only option, the guy knew names and had sensitive information, etc. Even after he got caught and the government seized his laptop with his encrypted drive mounted and got the keys to the kingdom they didn't find any other instance of anything like the alleged murder-for-hire plot. The government inducing the crime and the defendants lack of a predisposition for that specific crime are the two elements to an entrapment defense in federal court.

Because he wasn't actually charged with the crime he didn't get to mount any kind of defense against those allegations and the prosecutors just hid all of the corrupt B.S. involving Carl Mark Force IV and Shaun Bridges. I think Ross is guilty as sin of running the Silk Road but that trial was a huge miscarriage of justice and in an ideal world, a bunch of those prosecutors and law enforcement agents would be sitting in prison right beside him. Alas, only two of them are. I really feel like the Supreme Court should have overturned his sentence based off of not receiving due process for the murder-for-hire allegations yet being sentenced substantially worse based off of it.

He wasn't charged with any kind of homicide charge, but the murder-for-hire scheme was a predicate of his conspiracy charge; in other words, he was charged with the murders, under a (much) lesser charge of conspiracy. The state had the burden of establishing the murder-for-hire scheme, and the defense the opportunity to knock it down; contrary to popular opinion, it was an element of the trial.

It is highly unlikely anyone with any DarkNet experience would think they could use it for murder for hire. It's the sort of thing you can claim without any evidence and your average citizen would believe at face value.