I distinctly remember listening to recordings of him hiring a hitman. It's been a long time and my memory is certainly prone to error, but that sort of thing does stick with you. I especially remember the irony because he also preached about non-violence at some point, obviously until someone's continued existence became inconvenient for him.

I don't agree with that and I don't understand why those charges were not taken to court (I don't believe it was purely because he already had 2 life sentences as when the appeals were going to the supreme court and there was a risk of him winning, it surely made sense to secure him if you had the evidence to proceed with another case). Whether that was true or not though, someone can only be sentenced and punished on what one was convicted of. Anything else is not based in justice or law.

I don't really believe that the US is a country ruled by law any more, but in some idealized land of the law you are probably correct. But you won't convince me that OJ Simpson walking on a double homicide he clearly committed is justice. For Ulbricht, it actually feels like things more or less balanced out, but he did try to have someone killed, and I don't think that's a nice thing to do.

Did the judge conclude, as part of sentencing, that hiring a hit (or two?) was likely?

What reasoning did the judge give for the sentencing? They might involve similar websites but the crimes can be much different. Two people can run the same drug cartel at different times, but that doesn't mean their crimes are the same.

I think one can say the sentences were too severe and still think some sentence was fine.

I would agree with this. He deserved punishment as he did break the law.

Your link says that was a court in England. England generally has different sentencing standards than the US.

Valid point, however even those involved that were comvicted in the US such as Brian Farrell only received single digit sentences.