America's racial classifications follow a very practical application rather than some grand racial theory. this is a good thing, because as we know race is more a phenotype than genotype. thus arabs are grouped with whites because, according to traditional racial classification, they are caucasoids. there has been no adjustment to this because immigration from the middle east has not been a huge number since those days. indians (south asians), also considered caucasoids in the 19th century system, are however lump-summed with asians (mostly mongoloids), for practical reasons. the practical reason has to do with socio-politics. for now, indians have similar immigration and social characteristics in common with east asians. thus categorizing them together has a practical purpose with respect to social services, immigration policy, etc.
as you can see, classification is a tricky problem. america's classification is constantly evolving. every 10 years america takes a census and every time there is a change in the boxes for race categories. this is an attempt to keep pace with changing views. it's not a perfect system but it's not bad. it certainly beats france's system (which literally ignores all racial categories according to principle--leading to all manner of unintended negative consequences including inequality towards recent immigrants or citizens of color).
as you can see, classification is a tricky problem. america's classification is constantly evolving. every 10 years america takes a census and every time there is a change in the boxes for race categories. this is an attempt to keep pace with changing views. it's not a perfect system but it's not bad. it certainly beats france's system (which literally ignores all racial categories according to principle--leading to all manner of unintended negative consequences including inequality towards recent immigrants or citizens of color).