You're misrepresenting your case here. The law stops you from tinkering with the software of the tractor. You can tweak, repair, replace, or light on fire any part of the tractor you want, so long as you do not reverse-engineer the software inside the tractor. So technically, the law does not stop you from repairing any of the mechanical parts of your tractor.
I'm not saying I agree with John Deere's attempt to prevent people from playing around with its tractor software, but I am saying that you're exaggerating here.
I'm not saying I agree with John Deere's attempt to prevent people from playing around with its tractor software, but I am saying that you're exaggerating here.