The quote means that to be a part of your community, you have to be like everyone else. If you are not like everyone else than the other people in the community will just ignore you or treat you as an outsider.
Immigrants should not abandon their home culture. People need to have a strong identity to be happy healthy individuals. Having pride in your heritage gives you a sense of identity. No one and no country stands alone. Every country has contributed something to the world.
