Yes, our ancestors created racism as it is currently practiced in the West. Chaining up an entire generation of people, bringing them over an ocean, and telling them and their grand-children (And our grand-children, so that we don't forget to remind them) that they aren't human kind of covers that.
In short: racism and slavery existed since time immemorial. Only recently western culture started doing something about it.
"white" as a category is just as non-sensical as "black" as a category. these are very course labels for phenotypes and say very little about a person's ancestry or heritage. When I meet a black person today, in New York City where I live, I don't know if they are the descendant of American slaves or if they are a 1st gen immigrant from Nigeria. The only sensible thing to do is treat people as individuals and judge them by their own actions.