My point is that the US government was always obsessed with defining whiteness, and the immigration laws reveal that. You suggest, for example, that Jews were not white in 1790, yet they were: George Washington praised Jewish immigrants and spoke of their citizenship that very year: https://founders.archives.gov/documents/Washington/05-06-02-0135

Americans who grew up after Kennedy's election have trouble understanding that Protestantism and whiteness were separate concepts, so people could have the legal advantages of whiteness without having the social advantages of Protestantism.