Agreed, if Ulbricht hadn't tried to call a hit out on someone, life in prison would seem unreasonable. Based on the information we have, though, it seems pretty certain that he did.
Whether or not the hit went through, he tried to do it, which definitely puts him on the sociopathic spectrum.
If I had a button on some website that would cause someone to be killed, I wouldn't click it. A button on some website that enabled people to get the drugs they want, though? I wouldn't have quite the same moral quandaries.
Don't get me wrong, the hard drugs are bad and in essence the people who use them pathologically are victims of their own brain chemistry; I'm just not so certain that life in prison for someone who enables that is actually a solution to that problem (but the effectiveness of prohibition by force is a whole 'nother story).
It seems clear to me that the motivation for the prosecutors and LEOs involved is to crush the concept of an unregulated, international, black market. I'm definitely not convinced that this prosecution will actually produce the desired goal. Silk road was just the first of many darknet black markets that emerged to fulfill a need. Others are still thriving and as they get shut down, more will spring up in their place, gradually improving their ability to evade detection/termination.