It suggests that Groucho believes the writer of the original letter knows as little about the city of Casa- blanca (his history is filled with absurd details) as he knows about how different the Marx Brothers' film A Night in Casablanca would be from the famous Casablanca.
Morrison wanted to show how hurtful racism is
a friend is a person who has strong liking for you and have trust in one another, a compatriot is a is someone from ones own country. hope this helpes!
