As a result, populations poorly represented in 1890 were prevented from immigrating in proportionate numbers—especially affecting Italians, Greeks and Eastern European Jews, as well as Poles and other Slavs.[1][3][4] According to the US Department of State's Office of the Historian, the purpose of the act was "to preserve the ideal of U.S. homogeneity."
https://en.m.wikipedia.org/wiki/Immigration_Act_of_1924
Of course they didn’t have it as bad as black Americans, but that isn’t the topic of this discussion.