The myth of multicultural America is just that, a myth.
Until 1965 the vast majority of the people came only from Europe (not all continents, not ‘all colors’).
“The Melting Pot” was a play written by a British writer not policy. The ‘pot’ was full of White European peoples, not the world.
As Stephen Miller so clearly explained to a dumbfounded press the poem connected to the statue of liberty (well after it was built) is just that, a poem. It was not, nor meant to be policy (which had clear racial restrictions and quotas).
Have you ever been to San Fran? I’ve never seen such a Chinese city, but it they are Chinese-AMERICANS - their families have been here since the Gold Rush and construction of the transcontinental railroad. I’d never seen Chinese policemen before, and they worked just about every job you’d see Anglos work anywhere else. Not a trace of an accent, no traditional garb - completely assimilated.
Where did the interned Japanese-Americans come from, or the Mexicans targeted by Eisenhower’s “Operation Wetback”? The Cubans fleeing Castro arrived here in NJ prior to 1965.
Maybe not all continents and colors, but certainly not limited to Europe - and those groups weren’t the public burden today’s immigrants often become.