I can't say I know every detail of the case but I don't recall anyone getting killed or even hurt by Mr. Ulbricht so in my mind the punishment does not fit the crime. IMHO the death penalty should be off the table completely (go Nebraska!) and life in prison reserved for only violent offenders. You can argue that he enabled people to harm themselves but I think that's stretching it. If people want to take drugs, even take too much drugs their going to get it somewhere. If drugs were legal and treatment of abuse the focus instead of punishment Silk Road wouldn't have existed in the first place.
The prosecution brought this up at trial but he was not charged or convicted of this in the criminal trial.
Go Team 'Murica....
Even the most ardent proponent of full legalization usually acknowledges that many drugs are very harmful--they just believe the people should be free to do things even if they are harmful to themselves.
I generally support decriminalization or even legalization, but I would be reluctant to allow internet sales. I'd require sales to be through licensed dealers and in person, so that an addict cannot completely cut themselves off from human contact. Internet sales make drugs too easy.
example: drop tons of Agent Orange on the lands/people of Vietnam? Just an oopsie! and they move on, wipe their hands clean. People dead and children deformed. Oopsie! Our mistake. Next meeting.