It would seem I have failed to make my point, then.

Choosing does not require that it be physically possible to have chosen differently.

Being able to say, "I could have chosen differently," does not require that it be physically possible to have chosen differently. It is a different sense of "could".

I am not saying that choice is an illusion. I am pointing to something and saying: "There! Right there! You see that? That's a choice, just as much as a calculator is adding numbers! It doesn't matter if it's deterministic! It doesn't matter if someone else predicted you'd do it or designed you to do it! It doesn't matter if it's made of parts and caused by the dynamics of those parts! It doesn't matter if it's physically impossible for you to have finally arrived at any other decision after all your agonizing! It's still a choice!"