The film focuses on an American unit - through out the entire film - and it wasn;t meant as a General D-Day landing scene. It focuses on the specific units landing on the beach. General ignorance of the other landings during D-Day has nothing to do with the movie!
I wasn 't in it. Having turned down a role in Braveheart - 3rd woad-painted warrior on the left - I had left Ireland for Oz so had to reject Mr Spielberg's offer. There are always going to be goofs/inaccuracies in films but once they are not glaring we can live with them.