Asian people

This post is old, the information may be outdated or it may no longer represent my ideas.

Why do Americans (or maybe some other people in west) only call eastern Asian people, Asian? Pakistanis, Afghans, Tajiks, Many Russian people, Iranians, Saudis, Omanis, and many other people are also Asians. Why do you (or them) don’t call us Asians?