Question

why assimilation is necessary

Answer 1

Assimilation is completely necessary to  be a productive American in society. You cannot be a productive American citizen or really a citizen at all if you do not conform to some extent to American law and culture. For example, if someone was to move to America from their own country yet still follow their home countries laws, they are not going to make good citizens and will probably get themselves in some trouble breaking American law. Also you must to some extent conform to American culture. Knowing English for example is not required but advised since it is spoken in America, used in signs, laws, and other applications. Also a knowledge in how things are done in America is also necessary to be a productive American.