Why is the team from Germany called "Germany National Team", not "German National Team"? On official Internet sites, it is the same for every official national team; Germany National, France National, Poland National, Russia National etc. etc. What truthfully bothers me is why not German, French, Polish, Russian etc?
Germany National is the formal name, in English, of the team that represents the nation of Germany. The phrase "German national team" is not the formal name, but describes the national team that represents Germany (and of course within Germany it is called the Deutscher Fussball Bund).
Germany National, England National, Spain National or [Country] National reflects the naming convention in use for the English language within the international football association. Don't confuse naming convention with descriptive terms. These are "Terms of Art", meaning they are artificial constructs or conventions, and are created for the purpose of consistency and recognition.
Germany National just happens to be the formal title of the German national football team - when spoken of in English.