For example white people can be racist against Jews who are also white. In South Africa the definition of race changed all the time. Some of my aunts were classified white, and their sisters were classified coloured. Some people had their race changed from black to white. This then has an effect on how people see amd organise themselves.
Racism is more than just intolerance.
It takes place at various levels institutional, cultural and personal. This is built into society. Also people internalise racism and think that they are inferior and that the white must liberate them. Such internalised racism must also be combatted. To take a black person into a white company and make her act white does not combat racism.