That's not what they're doing or why.
They're not here to decide his fate or his case, though that may happen incidentally. They're here to settle a legal question that was posed to them in the petition for a writ of certiorari.
It's not their job to try his case, nor will they. Unless the entire case hinges on this question (it doesn't), they don't decide his case. So they might unfreeze his assets while he faces fraud charges, but we're not looking at them deciding his guilt or innocence here.
They're trying to decide what the best precedent to set is, which is why they have to consider every possible scenario. So yes, they really do have to consider scenarios with guilty people. It really wouldn't make sense to have them blind themselves to how the precedent will play out in the future. Surely you do not believe this will never be applied to people guilty of fraud? They do consider doubt in such stories, but only when it's important. So they might do that if they were pondering the scope of reasonable doubt, but it wouldn't make sense here.
This case may involve him but it's not about him. It's only about the Sixth Amendment question posed. They're not concerned about all that other stuff because they're not deciding his guilt or innocence.
> Yes, the money might be able to get away. But you've arrested the person, and that's all you get.
The Supreme Court and prior cases disagree with you.
> Aside from the due process problems here, it's quite disturbing to see the government seemingly much more interested in the money than the crime. Something's wrong there.
Yes, but that something is your understanding of what they're doing and why.
Due process is your Fifth Amendment right. Nowhere does this case allege a violation of that right. This is not at all the same as a Sixth Amendment right to counsel being argued here. Moreover, he is in fact already defended by counsel of choice, specifically this one: http://www.royblack.com/attorneys/Howard/Srebnick/
This makes the hypothetical infringement of the Sixth Amendment rights rather oblique--was he really denied his right to counsel when the very expensive lawyer he chose is arguing before the highest court in this country?