A couple points:
1) My contention has always been that Cuba acted unusually aggressively in sentencing Gross to 15 years. You disagree, and claim that the 15-year jail sentence is only a "minor deterrent." By disagreeing with my point at all you are (by definition, again), implicitly arguing that there response was not unusually aggressive. Moreover, by using the phrase "minor deterrent" you said flat-out that he should have expected a lot more.
It's pretty fucking dishonest to claim Cuba was only "minorly deterring" foreign agents with a 15-year sentence and then argue he has never implied "a 15-year sentence is not only typical, but minimal."
2) You have repeatedly said Gross was convicted of "attempting to smuggle illegal contraband (after successfully smuggling more in earlier trips), with the goal of overthrowing the Cuban government, financed by a foreign (and openly hostile) country." You have accused gross of multiple separate crimes under Cuban law, and implied that are all perfectly within Cuba's jurisdiction. These crimes are a) being an agent of a hostile power, b) having a goal of overthrowing the Cuban government, and c) smuggling communications equipment. If Cuba could ban a), then the US could legally execute the entire Cuban bureaucracy because they are all agents of a power that is hostile to us. Since we can't do that to them, then any Cuban charges based on Gross's being a CIA contractor are clearly ridiculous BS. The same applies to b). Ukraine clearly can't charge all the Russian soldiers invading it with crimes in Criminal Court, therefore Cuba does not have the right to charge US CIA contractors for plotting it's demise.
Which leaves you with c).
3) The whole problem with your argument is you refuse to think what you are saying. For example this quote:
"What I did claim was that Cuba's sovereignty implies that they have no obligation to carve any exceptions in how they treat their prisoners just because of the passport that the criminal happens to be holding."
Words like "obligation" don't really mean much in relation to a) international law, or b) my argument. Under international law literally no country is ever obligated to do anything. There is no Starfleet sitting in orbit waiting to zap people for non-compliance. The way you zap people for non-compliance is you get pissed at them and ratchet up tensions. Most of the time this fails to get them to change their ways, but it's all we can do until we actually have One World Government with a Starfleet.
In this case, as I have proven, most of what Cuba charged Gross with are things it has no legal right to charge him with. They did it anyway. The remaining charge, smuggling computer equipment (the only thing he did on their soil), is the kind of thing that never results in a prison sentence. The US response to that has to be a cooling of relations, which (in Cuba's case) means and end to embargo-ending talk.
Which means either Cuba is full of people who are dumber then me, or they wanted to eliminate all talk of ending the embargo.