That's "two wrongs make a right" logic. Because the justice system fucked up in the past, even once, that should prevent anyone else from receiving a proper sentence?
Secondly, Ulbricht was an accessory to thousands of drug deals. You think that none of those consumers of those drugs died as a result? He could easily be responsible for multiple, dozens, hundreds of deaths - far more than most anyone locked up for life.
> You think that none of those consumers of those drugs died as a result?
All kinds of products kill consumers every day, and we don't consider the person who sold them responsible. And the suppliers of those products heavily encourage and even manipulate people into buying them; do we know whether Ulbricht even advertised his services?