I actually think this pardon may be reasonable. The sentencing in his case seems very dodgy - it was seemingly based around unproven allegations that he was violent rather than the proven crimes he committed. The violent crimes were decided on the "preponderance of the evidence" (I.e balance of probabilites) rather than beyond reasonable doubt, and his harsh sentencing has been controversial ever since. Preponderance of the evidence is used in civil cases, not criminal ones in English law (which also applies in US law).
He was convicted of continuing criminal enterprise, narcotics conspiracy, money laundering conpiracy, and conspirancy to commit computer hacking. He was sentenced to 2 life sentences plus 40 years, which was based on the possibility he'd commissioned murders (which never took place btw).
I can see why some argue this was a miscarriage of justice. I'm not an expert in jurisprudence so may be wrong about this, but as a lay person the sentencing in this case doesn't sit right with me.
I doubt Trump has any understanding of the nuance of this case nor cares; he clearly just regards this as a transaction with American libertarians.
