Caucasians have a genetic advantage
What?
He's talking in specifics. Caucasians
could have a genetic advantage when it comes to bubonic plague, just like most people have a genetic advantage to resist diseases that their ancestors came in contact with.
Think about smallpox and the Native Americans. The Africans and Europeans who came over had been dealing with smallpox for quite a while, so they had a genetic advantage compared to the Native Americans, who had never dealt with smallpox. This doesn't mean that the Native Americans were inferior, as there was likely some disease that they had been fighting for many years that could have hit the Europeans pretty hard.
It all balances out. Reading
this may help clear up what I've said. Or it may confuse you more. Your results may vary. (possibly depending on your ancestry
)