I take the SEAL Team Six example to function not as an example of a case where the ability to prosecute has a high practical importance (in part, for the reasons you give) but as a reductio ad absurdum of the Court's test.
That’s fair, and I can buy it as a broad “it’s insane that this would constitute official acts beyond the possibility of being questioned.
It’s the shift from rhetorical absurdity to “could it actually happen” where I hit the brick wall of “yes but the same way it could have happened last week”.