There is a cliche that goes, "everything after the 'but' can be ignored."
Usually white racists use scientific discoveries and other achievements to claim superiority over people with darker skin, commonly known as "Black." Others focus on the ability to colonize and exploit the bodies and resources of Black people as proof.
They will all concede that Blacks are stronger because, naturally, we are more primative, ape-like.
Sometimes Black people adopt these false beliefs as truth too. Why?
Whenever something is repeated frequently enough, no matter how heinous (or stupid) it becomes easier for people to believe. In a county like America, where the myth of white superiority has been drummed into the brains of the population for centuries, the lie becomes easier to accept. Indeed we'll craft our own narratives to help it make sense ... ultimately it becomes a moral conviction which is virtually impossible to dispel.
If you start with the false premise of race and accept that lie, you can then consider the idea that one so called race is superior to another. At that point you are primed to justify anything from eugenics to slavery based on skin color.
I know there is nothing I can say to help you think about what you wrote differently, so I won't try. I just hope others do not follow up down the same path.
This why I believe books are so important. But books by themselves are useless, if they are not read or can not be interpreted. Education is crucial, and as a culture we have dropped the ball on that big time.