Many immigrants are savages, of course; consider the number of Irish who have poured into this country, bringing their medieval attitudes and their p[enchant for breeding like rodents. However, many of the children of these backward peasants have adapted to civilised culture and a few of them now even lead useful, decent lives. Within 5 or 6 generations they may even begin to breed with native inhabitants of this Great Island Nation and their genetic problems will be watered down by the addition of pure English blood.
Immigrants from other cultures, sadly, have not integrated in this way, which makes it difficult to drive down Commercial St on a Friday afternoon.