It depends entirely on what that consensual activity is. If the activity is selling stolen credit card numbers, then it's facilitating theft and doesn't seem virtuous at all, since it's harming a third party. If it's exchanging kiddie porn, again it's harming a third party. If its selling malware, then it's a free exchange with the intent of violating others privacy or otherwise harming them, which does't seem virtuous at all to me. But those were all services that Ulricht not only knowingly facilitated, but worked to specifically facilitate. While I don't agree with the US drug laws, assuming he was responsible for the Silk Road, Ulricht was choosing to facilitate many sorts of exchanges that while consensual between the parties involved in the exchange, were exchanged motivated by profiting off the harm of other parties who weren't consensually involved, but were either victims of crimes or were victimized by the use of the product of the transaction.
"The indictment reads like a product of zeal and overreach, not a dispassionate document outlining a person's conduct and how it clearly violates plain language."
I dunno, they laid out a pretty clear case of what the law was and how it was broken in my reading. He was pretty clearly violating various criminal conspiracy laws that were written to deal with just the kind of thing he was doing.