Asians get hand-waved out of statistics for the same reason native americans. There aren't that many asians in the US. As the asian population increases, I'm sure you'll see more analysis.

Keep in mind asians were barred from immigrating to the US for much of the 20th century.

https://en.wikipedia.org/wiki/Immigration_Act_of_1924

The asian population in the US was effectively 0% ( less than 1% ) for most of the 20th century.

It wasn't until the 1970s that immigrants from asia started arriving.

Also, asians ( particularly asian women ) marry outside their race, so that stagnates the US asian population and hence limits the statistical analysis that can or will be done.

Maybe racism was a reason decades ago, but it isn't why asians aren't included in these stats. It's because there aren't that many asians in the US.

Edit: You will find asians in data where there are significant asian population - california/hawaii and college population. But generally, in overall US population stats, asians are left out because of their low population numbers.