Greetings Isvari,
Yes, I suppose using the term "Asians" is too much of a broad stroke, however, unfortunately, in dealing with filling out the US census or signing up for college, or taking the SAT's, or filling out one's medical history, all these forms usually have the one box to check, which would be Asian. Way back when the dinosaurs roamed the earth, all I had to choose from was the Pacific Islander box.
And yes, using the term HUMAN would be absolutely glorious in my opinion, but we would not be be to track statistics, allow certain monies to be allocated for particular services, or to wretch out lawsuits for the monies might be needed, especially in cases like Lau vs Nichols, wherein Nichols, case in which the U.S. Supreme Court on January 21, 1974, ruled (9–0) that, under the Civil Rights Act of 1964, a California school district receiving federal funds must provide non-English-speaking students with instruction in the English language to ensure that they receive an equal education. Hopefully, the lexicon will catch up with all the forms that need to verify one's citizenship or nationality.
Personally, I like the term Asians, because that is the sphere of influence I travel in. I have ancestry that is Spanish, Chinese Filipino, Japanese, and some others that my father has not told me about. I'd rather have that signifier, as opposed to guk, chink, slant eyes, china doll, exotic, dragon lady, oriental and all the other derogatory terms I have heard in my lifetime which defined me as an object and not as a "human".