Because you're asserting that the DoJ made their charging decision not through applying independent prosecutorial judgment, but in response to political pressure.

In Hunter's case, that appears to be correct.

Which is exactly what Trump claims happened to him.

Trump's claims are rarely coincident with the truth.

Here's my final thoughts on the matter.

Hunter Biden never tried to argue the process was unfair to him. He accepted the findings of the DOJ at virtually every step of the process. He never really claimed that he didn't commit the crimes which were alleged. He was ready to plead guilty to them until the DOJ caved to political pressure. That was an error on the part of the DOJ. Yes, Hunter pleaded innocent, but that was only because his plea agreement he was ready to accept fell apart due to political pressure. So he was forced to enter an innocent plea to protect his rights. He did all of this because he recognized that he WAS guilty and was prepared to accept the consequences. And his trials eventually did find him guilty.

On the other hand we have Trump crying and screaming like a spoiled brat that he didn't do anything wrong at any step anywhere. That is, of course, his right. On the other hand three different prosecutors in 4 different jurisdictions were able to convince 5 different grand juries (remember, the Jan 6 case went to a grand jury twice), that there was sufficient evidence to bring charges. Again, that doesn't mean he was guilty - only a trial can determine that - but it does show there was significant evidence of the crimes charged. And the one trial that did happen found him guilty.

Was there some political pressure in Trump's multiple cases? Perhaps. But at most that was in pushing the investigations to happen. I have seen no evidence that charging decisions were swayed by overt and improper political pressure. That is in stark contract to Hunter Biden where there was one and potentially two places where political pressure actually changed a charging or prosecution decision. And that was mainly pressure on the prosecutor running the case and from outside sources.

Would the error of falling to improper political pressure in one case negate the same error in a different case? No. Both are errors. And that assumes there were improper pressures in both cases, which is something I'm not willing to stipulate.

And don't forget the bottom line. Hunter Biden submitted to the legal process and let the process play out. He never claimed the process itself was unfair or incorrect. With all of the facts in the public domain and guilty verdicts coming as a result of those facts, the sitting President chose to intervene and issue a pardon, as is his right. Trump has never admitted guilt, nor has he claimed actual innocence. His claims are all an attack on the legal process itself. It is those attacks that damage the legal system, not the issuance of a pardon to a guilty person.

--Peter