The religious fanatics self-segregated and sent themselves, for the most part.

The political opponents would from Europe be a point to the positive side, at least pre-1917. German immigrants after 1848 tended to be radical Republicans, anti-slavery and pro-labour. One post-1948 German immigrant was August Willich, a German communist (he had previously challenged Marx for a duel for being "too conservative") who went on to become a general in the Civil War.

Britain seemed to like doing that sort of thing.