Precisely. I think either EA just forgot to include the yellow Redskins helmets or the Redskins requested they be removed (if so, that team should really be focusing on its myriad of other issues). That's the only way I can explain why the other throwback helmets are still in there (let's hope EA doesn't do something idiotic and remove those with a patch).
I understand the NFL wanting players to wear only one helmet during the season for safety reasons (not having to get used to and adjust to various helmets), but that shouldn't affect in any way what is included in a video game.
Makes no sense why the NFL would demand alternate helmets be removed yet allow a feature where we can relocate the Cowboys to Mexico City or the Redskins to London.