Racism is not an illness that can be treated with an educational course.
Unless it is some sort of indirect racism; In today’s era, everyone is well aware of what they are doing if they are part of some outwardly discriminatory activity.
They are also aware that if they are being racist, there is a consequence to it.
So even if their human part doesn’t stop them, at least the rational part, which should reason them out of punishment, should stop them.
It didn’t and they should be punished.