But why is that interesting? Neither of them are lawyers, and you don't need the federal government to grant a trademark to have one.

If someone wishes to address the issue on strictly legal grounds, such as by contending there is no trademark protection, then there is no choice but to bring in lawyers... All further discussion after that is just nonsense, such as the discussion of how Ubuntu uses their trademark — there's no point in trying to develop your own internal legal theory by reasoning with Ubuntu as a proxy.

Because it shows that the trademark was rejected.