There was all kinds of hatred for the Irish, Italians, Germans, Poles, Chinese, etc. 70–150 years ago.

Interracial marriage was illegal in the US south less than 50 years ago.

The arguments against Mexicans and Muslim refugees today are nearly identical, just with the names changed.

1940s Sinatra: https://www.youtube.com/watch?v=UpO6mpYvyqQ

I guess there was also hatred for the English and the Spaniards the first time they put their feet on american soil...

According to old diaries in my family collection, even my german ancestors detested working for the English "lord" in the late 1800s.

The US was the sum of N European cultures, mostly western, mostly northern. So assimilation wasn't as big a leap.

There's not really a good response I can think of here which fits with the guidelines of this site aside from basically we have a lot of ignorant short-sighted voters in this country.

One of the reasons Clinton lost is because of the attitude that everyone who opposes her is ignorant and short-sighted. Food for thought.