... if you come from a foreign country you should assimilate ...
That's exactly what immigrants today are doing, just like those who came before them.
Today’s immigrants assimilate faster than the Europeans who came before them
"Many assume that the European immigrants of generations past assimilated quickly, unlike Latin American, Asian, or Muslim immigrants today. Not true. Lasting ethnic enclaves like Greektowns and Little Italys were typical. Today’s immigrants actually learn English and forget their native languages faster than did the earlier newcomers. Similarly, romanticized memories lead many to believe that, unlike today’s immigrants, their ancestors made it up the ladder on their own steam–also a distortion. In the end, the supposedly unassimilable children and grandchildren of earlier immigrants became regular Americans, often to the chagrin of parents who hoped that their traditions would be more lasting."