You are implying a use of the term which is more influenced by biology and some vague, folksy notion of genetic/darwinian relation, often focused on skin color etc. I understand your distinction. but it is, almost by definition, more modern.
They can all align to (mostly) one group, like in India and China, or can be mostly aligned like in northern Europe, or a melting pot like the US.
It's the "connotations" (i.e. conflations) that are the reason that almost everything is labeled "racist".
The concept of race very much predates our understanding of genetics, which is a relatively modern science.
My wife is Chinese, and feels a racial kinship to Asian people from many countries: Japan, Korea, Vietnam, ... Refers to all as Asian.
As stated, they were not. Race and ethnicity (and also words like breed and stock) were much more synonymous 100 years ago. If you aren't keenly aware of semantic shifts like this, you will misunderstand older texts.
I'm also not sure if you're actually suggesting that China and India are (by any definition) racially and ethnically homogenous. If you are, I must encourage you to study those countries more.
There is absolutely no scientific basis for the racial categories used today.
Apart from the fact that the genetic differences between all humans are tiny compared to different races in animals (which is I guess where the term comes from), there is also the fact that many ethnicities which are lumped under a common race differ more from each other than from many other "categories", e.g. Africa has more genetic diversity than all other continents combined. Therefore one "black" person might differ significantly more from another "black" than from a Caucasian or Asian person.
I mean the irony that there is the "racial" category of "African-American".
I think this is also not just semantics. The use of the term race associates much larger differences than there actually are, which makes it easier to justify discrimination/hate.