"This goes beyond politics. Legislating little nooks and crannies paves the way for doing away with copyright altogether."
I highly doubt that. I keep hearing the same lame arguments why it should not be allowed, but when you transfer those arguments to other products (buying a car and modifying it), the arguments fall flat on their face because it is bad logic.
That's because the car example is the same as "your personal copy for fair use". If you start modifying all the cars you can, that's a problem. Your own is fair game.
With a car the difference is that the person modifying it isn't making a copy of it.