And the white people are granted an additional $25,000 in equity for no reason other than being white people surrounded by other white people.
$25,000 is a lot of money, last time I checked. I imagine you'd get a lot further ahead if somebody dropped $25,000 in your lap.
So a white person looking out for the best interests of his family, armed with this knowledge, would tend to stay in a white neighborhood to get the higher property values, even if he had no particular racial preference. The discrepancy becomes self-perpetuating.
Thus the economic legacy of racism can persist for a long time after the racist at udes fade.
You are largely correct that the overtly hateful racist at udes have faded over time. But racism is not always the same thing as racial bigotry, hatred, or oppression. It can stay embedded in the system for a while.