Dude, get over it. They were sending a message and equate him with Pablo Escobar or Joaquín Guzmán. If half the citizens of the U.S. signed it they wouldn’t let him out.
Upon reading the sentence, Judge Forrest explained she was making an example of the 31-year-old Ulbricht to send a message to others like him. The Wall Street Journal's Nicole Hong sums it up well:
"Ultimately she gave Mr. Ulbricht the harshest punishment allowed under the law, saying Silk Road was 'an assault on the public health of our communities' by making it easy for people around the world to buy illegal drugs. In a passionate speech, she detailed the ways drug addiction can tear families apart.
'What you did with Silk Road was terribly destructive to our social fabric,' said Judge Forrest, who also ordered Mr. Ulbricht to forfeit about $183 million."
This isn't to say that Ulbricht isn't a lousy guy because he almost certainly is. The court documents clearly paint a picture of an unrepentant man who sought to protect his illegal empire by "violent means, including soliciting the murder-for-hire of several individuals he believed posed a threat to that enterprise." Andy Greenberg of Wired describes how these particular details -- which, it should be noted, were not part of this trial -- led to Forrest's decision:
"With those attempted murders as context, Forrest was merciless in her assessment of Ulbricht’s seeming multiple personalities: the altruistic and admirable young man described in the letters sent to her as evidence of his character, versus the callous drug lord she saw in his actions."