Yup asia is more of a geographical construct rather than one based on race but middle eastern ppl are not considered ang moh either but in the US they are considered white as they judge one's race based on physical appearance which is also not accurate as there are a lot of Chinese looking races around like viets, north east indians etc that look Chinese but that's where it ends.
The thing is to the western world arabs and the like are all considered to be a part of asia. They are classified as the near east, middle east and called oriental.
No. I lived In USA. In USA the term Asian is equal to East Asian (CJK) as CJK was the first Asian race to take root in US and also in highest numbers (compared to U.K. where Asian means ah neh). American awareness of Southeast Asia is limited to Vietnam and Filipinos (for obvious reasons: war and colony) and the migratory patterns from both VN and PH are also rather recent (from 1970s) compared to the long established roots of C and J in USA. Americans have ZERO impression of austronesian Southeast Asians (Malay & native Indonesian), while US politicians associate it with Islamic terrorism eg Clinton attacked Obama "grown up in most populous Islamic country in the world" in its campaign at the democratic primary against obama in 2012.
Arabs are classified by US fed gov as "white" in census but in American minds, they know culturally Arabs are not white and are have their own racial/cultural group (Arab, middle easterners). If we disregard what Americans think, the truth is genetically middle easterners and Arabs are much closer in DNA to white Americans than to East Asians (this fact can be easily seen by just observing physical attributes). It is no wonder, because white Americans are European descent and Europeans all came from the Caucasus region (near the Middle East), that's how they got the name Caucasian. Middle East is just below Europe sharing borders. In fact Europe and Asia are actually one piece of contiguous land mass. It is the whites who came up with two separate names Europe to separate themselves from Asia (they were dominant in the 1900s onwards and propagated this). They consider themselves too different from middle easterners and the rest of Asia. In fact the entire piece of contiguous land mass Eurasia has totally different cultures and RACES (so there's no such "Asian race"). The CJK sinosphere bloc, the southeast Asians (separated into austro-asiatic and austronesian), the Dravidian ah neh bloc, the middle easterners, the Central Asians (-Stan countries bordering China) and the Siberian Russians. Europeans were too ignorant in the 19th century to know that. Indian culture is highly influenced by Middle East (you can tell from the breads). Indians spread their culture to the Southeast Asian backwards austronesians in the 17th century onwards, in fact the austronesians were Hindus originally and much later then became Muslims.
Some Vietnamese (less than half) have varying degrees of Chinese looks because those that do actually have han Chinese DNA admixture- when the Han Chinese from Guangdong invaded and colonized Vietnam for a good 1,000 years (one can tell easily how different Vietnam kinh look from Khmers, Lao and Myanmese nearby). Many viet kinh have up to 50% Han DNA. All Vietnamese and Korean family names are originally Chinese and have a Chinese counterpart.
https://en.m.wikipedia.org/wiki/Chinese_domination_of_Vietnam
The name 越南 south of Yue refers to south of Guangdong (粤) means cantonese. That's how Vietnam became sinocized. Vietnam is the only country in SEA whose natives are part of the sino culture. No North Indian genes (or south for that matter) originally looks Chinese if you see any Indians who look Chinese, they are actually mixed (very prevalent in Nepal). North Indians look closest to Arabs and Mediterranean people. Indians, Arabs and ang moh are all under the Caucasian category.