> It is not so simple a problem. Should people have the right to do whatever they want with hardware they buy? Yes.
It's actually so simple you answered it right here! It's John Deere's problem to comply with the regulations we as society require of them - that is the cost of doing business.
That part is easy. How much we require John Deere to do to support people repairing their tractors is not.
A tractor is not exactly bleeding edge technology...