Is there anybody that does not have mixed ancestry? Where are the human labs and poodles?
The only real argument is that discrete categories do not exist. What this means is that for the vast majority of cases, the expression of phenotype A is not strictly linked to the expression of phenotype B. That said, it's quite obvious that there is a geographical and cultural distribution of genes.
Humans are not dogs, our populations are not strictly controlled for the purposes of winning dog shows. Attempts to do so are racist, in that they are (scientifically misguided) attempts to create or purify a race. Such as when your parents don't want you to marry someone who doesn't look the same.
The problem is only that there are not discrete categories. For starters, how do you classify children of parents belonging to two discrete racial groups? And their children? And so on and so forth. Well, people have been spreading their genes around the globe for a long time, and the upshot is we all belong to the same racial group. Sure, there are clusters, but there are not purebreeds.
Further, culture / ethnicity is just a much more accurate way to classify people than genotype or phenotype. I don't have a source for this, but I believe the best way anthropologists have come up with to group people is by the kind of food they eat.
I'm repeating myself here, but per WP, "Scientific racism is [...] alternatively the practice of classifying individuals of different phenotypes into discrete races."
Different races cannot interbreed, but only because they are geographically isolated.
Different species cannot interbreed (generally speaking), even if they are not geographically isolated.
Humans are not geographically isolated. Geographical barriers have contributed to the creation of population groups, but these are distinct from races in that there is a mechanism for DNA to move between them (somebody takes a trip and makes a baby).
Anyway, Wikipedia says in the lead sentence of that article I linked to that simply classifying people into discrete races is scientific racism.
"Scientific racism is the use of scientific techniques and hypotheses to support or justify the belief in racism, racial inferiority, or racial superiority, or alternatively the practice of classifying individuals of different phenotypes into discrete races."
There's a scientific meaning behind the word race - geographically isolated population groups, or more precisely groups that do not interbreed. Humans don't have those, and never have had those. I never said we were homogenous, any nitwit can see that most people in Asia have black hair, and there's no reason to think that only superficial physical characteristics sort geographically. Just that, there aren't distinct races. You know, a middle ground, as proposed by the guy who wrote that first article you linked to, at the end.
No, it's because he said it was due to genetic differences between population groups. This makes him a "true" racist in that he believe there are different races, or sub-species, of homo sapiens (sapiens). There is a scientific consensus that this is not the case, because races only exist if population groups are completely isolated, which humans never have been.
The only real argument is that discrete categories do not exist. What this means is that for the vast majority of cases, the expression of phenotype A is not strictly linked to the expression of phenotype B. That said, it's quite obvious that there is a geographical and cultural distribution of genes.
Humans are not dogs, our populations are not strictly controlled for the purposes of winning dog shows. Attempts to do so are racist, in that they are (scientifically misguided) attempts to create or purify a race. Such as when your parents don't want you to marry someone who doesn't look the same.