He was a drug dealer
My first thought was that Ulbricht didn't sell drugs himself, so shouldn't be found guilty of drug dealing.
But normal drug dealers are just middle-men between drug producers and drug consumers. That's exactly what Silk Road is. So yes, I guess Ulbricht WAS a drug dealer, with the aid of software in this case. He was a part of the chain, not an innocent bystander. He doesn't even have the excuse that he came from a challenging background where drugs were commonplace and there were no other employment options. He simply made a cool and calculated decision to sell drugs for profit.
For a first offence, lifetime without parole is too severe, and I believe he is sincere in his remorse which should also be taken into consideration when sentencing. As usual, internet crimes are punished more severely than real-world crimes, which I fundamentally disagree with.