The implication of what you say — that white and black are races — is that indigenous Australians and African Americans are the same "race", because they both have black skin?
There's no need to torture semantics. We all understand how the terms "black" and "white" are used in the English-speaking world. They are umbrella terms with varying usage depending on what superset/subset of people you are talking about in the moment. E.g. in the US, "black" usually refers to dark-skinned people of African descent (I assume you know this), but other dark-skinned people might be included depending on context. Yes, biological/genetic "race" is a many-dimensional spectrum, in which context it's fine to argue that "race" doesn't exist, but that doesn't make the colloquial words used to describe "race" meaningless. It just makes their borders fuzzy when mapped onto a biological context.
There's no need to torture semantics. We all understand how the terms "black" and "white" are used in the English-speaking world. They are umbrella terms with varying usage depending on what superset/subset of people you are talking about in the moment. E.g. in the US, "black" usually refers to dark-skinned people of African descent (I assume you know this), but other dark-skinned people might be included depending on context. Yes, biological/genetic "race" is a many-dimensional spectrum, in which context it's fine to argue that "race" doesn't exist, but that doesn't make the colloquial words used to describe "race" meaningless. It just makes their borders fuzzy when mapped onto a biological context.