I'm not missing your point and I don't actually disagree with your points here about protection or option. The fact remains you don't get to control everything in your life. Sometimes other people or entities have the power to do that for you and on your behalf, whether you request it or not. Sucks, I know, but that's how it works.
The car you've chosen to purchase has a wonderful benefit of being upgradeable for its lifetime. Those upgrades coming via the airways, at convenient times and for free, and without your permission. But like a coin, there's another side, and in this case you'll be recieving an upgrade (or downgrade) that you don't personally want. Again, without being asked. You take the good with the bad, or you buy cars like I do that are base models with hand crank windows and as few electronics as possible.
You knew all this going in or else you didn't do enough research. You can at this moment in time decide to take a deep breath, live with what you have, and be patient. Wait for the NHTSA's findings and if/when they find nothing of concern on the Model S, Tesla will send out another firmware update that gives you the option back of lowering your car at highway speeds - and it seems additional options in that category. Or, you can raise your blood pressure, stress out, and be upset, then still wait for the NHTSA's findings and the subsequent firmware update.