You’re jumping ahead 500 steps! Scientist cannot isolate the specific genes that give physiological advantages for running speed. So when I use the generic term “fast genes” I refer to the genes (not yet discovered in humans) that give physiological advantages for speed.
Getting back to your earlier statement
“Yeah, it is just cultural factors that >99% of the top 500 times are of people of West African descent from varying socioeconomic conditions (different family backgrounds, some being adopted, some in warm weather, some in cold, etc.) around the world. Total coincidence.”
This is a common error in logic. Your making an inductive inference based on one group of data. Now if I adopt the same logic, than Caucasians make better weightlifters & Swimmers, East and south Asians are superior divers and gymnasts etc! Now what makes your argument even more problematic is predicting future performance. Are weightlifters, divers, gymnastic, swimmers going to have a performance threshold based on race?? The whole argument just fails.