KEERIST, it's on it's way to achieving tax code status knowledge just to ride a bike in CA.
That's the way it is in most states. There's a regular license for the majority of us, a commercial license for carrying freight, a special one for driving heavyweight articulated freight vehicles, another one for carrying passengers, and another one for operating a motorcycle. Those are the usual breakdowns, with additional endorsements depending on if you are carrying hazmat, large numbers of passengers, schoolkids, etc, each with different requirements.
Trying adding an M1 endorsement to your California driver license and watch the California, motor vehicle, insurance condors circle. Try having an accident with a motorcycle involving the assistance of the CHP and watch the rates on your auto insurance skyrocket.
I have sympathy for the Austrian. I also appreciate why he didn't get the M1 endorsement.