The same is true for men and women for a wide range of characteristics yet we sometimes find useful to differentiate one from the other in some contexts.
In the last 11 Olympics, men with Sub-Saharan African ancestry have earned 87 of 88 finalist berths in the 100m dash. Is this random chance or does race correlate with some genetic traits enabling differentiation in physical abilities?
>grouping people by skin color or many other arbitrary groupings
This isn't arbitrary, when common ancestry and origin impart real world observable differences in a repeatable predictable way.
>there are groupings of people by genetic traits and things like that do matter
Yea exactly.
That's not a race. That's a particular tiny subset of a particular region with unique genetics. It's not even "Sub-Saharan", it's specific regions and tribes in Ethiopia, Kenya, and other rift countries.
> This isn't arbitrary, when common ancestry and origin impart real world observable differences in a repeatable predictable way.
Where they do, great, but often the standard "racial types" share little if anything. Skin color dictates almost nothing about the other traits of a person, so if you're concerned with "how fast do they get a sunburn", by all means group away. If you're concerned with IQ or athletic ability, try again.
First, you're completely forgetting culture. Second, nobody is claiming that there is no genetic difference between humans, it's just that the races we define don't correlate very well with them. Sub-Saharan Africa has the most human genetic diversity, so why would they be all of the same race?
Notice how they all come from specific population that is a small subset of black race. Probably more black people run slower then them than there is white people in total.
If you noticed that 99 of 100 finalists of some jumping discipline were Ashkenazi Jews or western Slovenians you wouldn't claim that white race is awesome at jumping.
That's why concept of race is useless. It focuses on superficial differences and similarities ignoring the real significant ones.
To take an empirical equivalent, imagine if someone gave you two lists of people, one of whom was "tall", and the other was "short". And you measured the tall and short people, and there were people in the "short" group who were taller than average for the "tall" group, and vice versa. Their height as compared by means and standard deviations didn't vary substantially.
At that point, your assumption should be that the labeling and grouping was wrong. So too for grouping people by skin color or many other arbitrary groupings like ethnic groups and national origin.
That being said, there are groupings of people by genetic traits and things like that do matter - the classic example being broad African-American susceptibility to certain genetic-influenced illnesses like diabetes and heart disease. These are markers that more recent African immigrants don't show, and are likely a result of strong genetic and epigenetic selection for certain kinds of robustness as a result of the historical conditions they were subject to, i.e. slavery, discrimination, and poverty.