This is a pretty pedantic debate but my reason for using it was that I think a factor in this wasn’t just generic anti-Asian sentiment but also the idea that they were new and challenging the image of the United States as a white country. California politics had a nasty “yellow horde” streak which feels distinct from, say, bigotry directed against native Americans or, in the south, Mexicans which tended to recognize their historical presence, treating them as kind of hapless children needing white guidance rather than invaders.