American Ideals - Roosevelt

In Roosevelt's American Ideals he says that to be Americanized is to throw away immigrants old ways of life (the "old world") and that in order for America to be great they have to do this. He doesn't think that it is wrong to demand that people that immigrate to America strip themselves of their culture to be "Americans". As long as a person is acting "American" it doesn't matter where they were born, but the key is to not show where you were born. Now the modern idea is to embrace cultures that moved to America from elsewhere. These needs for strict "Americanization" is no longer needed. I guess my question is why do you think it was considered bad for America to celebrate the "Old World" as Roosevelt calls it? To me he wasn't very convincing with his "spirit, conviction, and purpose" making Americanism. America was built on many different groups and that is what I think of as the American "spirit". If you don't act like "proper white America" you should just go back from where you come from?

All the reading about Americanization reminded me of the West Side Story song "America".