This is a cult like approach. The main proposition "Everyone is a racist, whether you know it or not", is an overstatement. There is no way you can tell "everyone" is a "racist", is just an aphorism with multiple interpretations. This has become the tool of identity politics and group thinking, throw and aphorism and let people fight over it. Unfortunate.
Hm. Humans are built to identify with a group, absorb culture, and be uncertain and uneasy when not in their group or their culture. That can easily lead to treating different people differently, and to the conclusion.
It's not completely true though. We usually reserve the term for active, conscious acts. Not just unconscious bias. So maybe we need a new word for that?