No, really it's not. America has been changed for the better by many immigrants who had "ideals and ethics" quite counter to what dominated American society at the time. Many European Jewish immigrants, for example, fought for labor rights and racial equality based on their treatment in their home countries. This was much to the chagrin of anti-Semitic "titans of industry" like Ford and Disney, who are absurdly still held up as paragons of American culture.

The dynamism of American society exists precisely to the extent that we don't let unthinking appeals to the validity of the status quo guide our behavior.