Pretty sure your uncle doesn't drive his back hoe 120km/h down a public road. Also atleast where I live back hoe equipped tractor needs to be licensed, driven by tractor licensed person to travel down public road. If it isn't so, it needs to be trailer loaded from work siteto another.
Also tycally to commercially operate heavy machine either industry regulation or just business sanity demands trained operators.
I would note, you don't need drivers license to drive a car on private closed road. Go crush oneself in car volt on private yard all one wants, the issue is untrained person driving on public road endangers others. That is why there is also demand for traffic insurance for the other parties damages, not ones own damage.