> We have always been at least somewhat tolerant of massive waves of migration, whether they were Germans, Italians, Irish, British, Chinese

The US wasn't tolerant. I don't even know where to begin. A single comment cannot convey how anti-immigrant the US was.

Nativism took hold of the US when the Irish and Germans arrived (mainly due to religious reasons & also fear of cheaper labour) Given that Italians were majority Catholics, they'd have the same intolerance shown. The Chinese were also hounded.

Laws were passed to discriminate against all those groups.

The only people who possibly got off lightly were the British (due to same religion & culture)