It makes sponsors feel good about the money they have given you!
He won all that he could win, therefore he won.

GT class winners at Le Mans all say they won Le Mans, same principal. SEAT used to promote themselves as World Rally Champions in their dealerships, when those of us who followed rally knew that it was F2 World Champions, general public wouldn’t have had a clue I doubt.

I’m not sure why it bothers anyone so much. These guys and their sponsors need something to promote or why bother.