In the US vernacular, the term "Asian" is equivalent to "Mongoloid", departing from the actual dictionary definition of the word. This common use (or misuse, rather) of an indicator of geographic origin as a "genetic" or 'racial' marker has led to a skewed, confusing view of Asian identity in the US. In the U.K., the term 'Asians' is popularly used to apply to all people from Asia, including South Asians. In East Africa, when people speak of Asians, they are usually referring to Indians, the largest Asian group in East Africa.
Indigenous populations of Asia are Caucasoid, Veddoid, Mongoloid, if one is to used outdated 'racial' classifications. But most non-Asian Americans only count brown and yellow 'Mongoloid' people as 'Asian'. West Asians (people from the Arab countries of Asia, and people from Iran) are counted as 'white' in the U.S. census. To add to the confusion, Indians and Pakistanis, who arguably resemble Arabs more than they resemble Chinese and Japanese, are classified as "Asian", specifically "South Asian". If you look up Webster's dictionary definition of the word "Caucasoid", you will see that it mentions the people of India. But when a white American heard the remark, "Indians are Caucasian", his reply was "but I thought Indians are of the Asian race". Poor guy, someone has to break it to him that there is no such thing as "the Asian race". And he probably can't imagine that one can be Asian and Caucasian at the same time.
The acceptance of 'racial' definitions originating in Euro-Am ignorance by Asians/Asian Americans themselves is a major impediment to cross-cultural exchange and organization among Asian Americans whose ancestral homelands on the Asian continent, though politically distinct, were historically linked by trade, diplomacy, and cultural and technological exchange.
Iranians and Arabs from Asia may vehemently refused to be identified under the banner of "Asian", since that word has been identified with the yellow race, which is supposedly inferior to the white race. South Asians may assume that they have no place in "Asian" organizations, which tend to have a membership consisting mostly of 'Mongoloid' Asians. This leads to a vicious cycle in which the lack of non-Mongoloid Asian representation in 'Asian' organizations leads to the further alienation of non-Mongoloid Asians from Mongoloid Asians, and setting up of separate organizations for South Asians and West Asians. Specific organizations for specific communities are fine and good, as each community has unique issues, but think of how much stronger we can be if we can, in addition to organizing under specific Asian communities, also join together under a common Asian movement that crosses 'race' and color lines.