As an older white American male, I don't feel guilty about slavery.

However, I grew up with racism all around me in my family, as did just about every white American I know.

We are responsible for our current behavior, which is to stand loud against racism and acknowledge the effects of 500 (not 400) years of oppression did to an important sector of our population.

There is no need to over analyze this. It is a very, very simple proposition.