No, “blacks” is not a catch-all term for non-white. Again, it means people whose ancestors are from sub-Saharan Africa. In fact, in the US it is usually even more specific than that, since the vast majority of black Americans’ ancestors are from West Africa specifically.

Similarly, white people or “whites” usually refers to people whose ancestors are from Europe, even though there are other people with light skin tones throughout the world (especially Asian or Native American people in high latitudes).

Not really sure what point you’re making.