Coy, i added the link to your OP.
This actually doesn't surprise me. Its a safety thing. Im sure they wont pull you over for nonsense like this all the time. i mean, look at how many people ride with streached tires. But I can see why this is done. Hell, Dopematic (dillon) debeaded his tire spinning off track. Who knows what will happen if its a 195 streached over a 15x9 wheel. I mean...you can hit a pothole, debead the tire, destroy your rim, possibly flip the car, kill people, and then sue the state for not filling in the pothole. Its just a law for the state to cover its ass over people being dumb, and wanting to sue the state over their own choices.
Its the same for driving on the street with DOT approved radials or R comps. They are legal, in fact once shaved to 2/32" they still have the DOT grooves down the center (Toyo RA1, other tires may have the grooves elsewhere) and you can still get pulled over and get a talking to, because its "unsafe to drive on the street" because you can hit standing water and spin and kill people then sue the city for watering the plants.
Thats my take on it, Its a more realistic approach to it.