I don’t really understand the subtleties of trademark and copyright laws.
I would have thought the creators of “The Simpsons” would have owned that name, at least for beer. I wonder if that German company or companies, could use “Duffman”?
My GGrandfather invented the road grader and got a patent issued for it but he never got a cent out of it. I think one has to really enforce them or people will simply ignore the patents.