>Now tell me... where, in this web of firing neurons is the "choice" exactly?

No idea! Nevertheless I am aware of having choices. I still don't see why your inability to explain why should cause me to doubt the reality of my experience.

>This is the opposite of an argument from ignorance. I'm not saying "I have no idea how free will could work", I'm saying that based on everything we know about how the brain works, and how physics works, the illusion of choice does not translate to actual choice.

Yes, physics can't explain it, any more than it can explain life or consciousness, because those things are all emergent properties of complex systems, not direct consequences of simple actions.