I agree with your analysis - the beuyer did pay for the feature, but there is one detail you got wrong: a manufacturer Monroney is only required for new cars.
The customer needs to go to the dealership and get their money back, and the dealership needs to go to Tesla and get their own money back
I think it was correct for Tesla to include it and I think their policy of non-transferable licenses is exploitative. Not legal in the EU but they can get away with that crap in the USA.