Taking computers out of the mix, if I ran a fraud ring from Russia defrauding US citizens of their money, I would expect a similar outcome.
But you wouldn't expect the US to agree to deport you back to Russia as part of the extradition assurance.
If anything, this is an indictment that the US penal system is so badly structured that people have legitimate claims of concerns over inhumane treatment. That the federal government has ad-hoc legal workarounds they can employ is likely a feature & not a bug at this point. It lets us keep this medieval system as the stick which puts us in more favorable situations generally for negotiating extraditions. I'm not saying this is good or a just system. I'm just saying that, without hearing arguments from legal experts, this doesn't seem out of the ordinary & I could see how we've rationally arrived at the status quo.
France and Germany are alies, both want to see said citizen punished. On completion of jail time the person would be deported anyway, so why not cut out a few steps and make the whole thing go a lot smoother. A bit of diplomacy behind the scenes to set it up saves years of back and forth defending their citizens rights while they are in jail in a foreign country, especially with high profile cases.
Australia have attempted this many times, bali nine for example, where they offered to jail them in australia, offered to pay life in prison costs, offered prisoner swaps, etc.
This just creates a situation where a criminal is deported to their home nation with an agreememt with said nation that they serve their prison time there. Nothing really that bizare at all.