I hear you. Generally when Americans say, "Asian", they mean, people from China, Japan, the Koreas, and to a lesser extent Filipino, Thai, Indo, Malay.. but mostly.
Basically, if you have smaller eyes, then you are Asian. Otherwise, you are Russian or Indian .. etc, sort of like how some people consider people from India, Pakistan, Sri Lanka and Bangladesh as "brown".
Continental unity doesn't mean much for Asia as much as it does for Europe or Africa.
Good luck correcting the millions. Just roll with it. Concentrate on whats most important to you.