They’re not. Arabs, Iranians etc. show up as Asian in the US though you’re free to pick whatever you want.
> White American, European American, or Middle Eastern American: those having origins in any of the original peoples of Europe, the Middle East, or North Africa. Following consultations with Middle East and North Africa (MENA) organizations, the Census Bureau announced in 2014 that it would establish a new MENA ethnic category for populations from the Middle East, North Africa and the Arab world.[18] However, this did not occur on the 2020 Census.
You're adding South Asians, SE Asians, Chinese, Japanese, Koreans, Mongols, etc all under the same umbrella