I mean, I don't know why it's a full pardon, IMO Ulbricht's sentence was far too long and harsh, I'm sure it was to make a point that others should not replicate it, but wouldn't a stay on the remainder of his sentence been a better option here ?
You’re assuming the reason for the pardon is “the sentence was unfair” rather than “some people that cheered at my rally said they would like me to do this”.
My understanding is that it’s more Trump generally attempts to keep campaign promises, he doesn’t always succeed, but when all it takes is an executive order, he generally does it pretty quickly.
In instances where it takes more than his signature (e.g. the wall) he has failed to make good on many promises but he definitely put in effort to trying to make them happen.
