You’re being needlessly pedantic and you’re trying to convince me of something that I already accept: race is a social construct that doesn’t scientifically exist. I know that. However, when I want to talk about Indian people looking more similar to each other than American people it’s kind of hard to simply say that without using race. Under your system I can only refer to every individual ethnic group of India or those of Indian national origin. Neither is what I want to refer to.
Also, since race is a social construct, you are incorrect that Indians must fall under the broader term Asian. They can be considered as Asian when appropriate to the discussion but they can fall under narrower or broader classifications when it is relevant to the discussion.