Critical Race Theory says racism can be subtle and unintentional. It is not a fringe idea.
The idea behind Critical Race Theory is that most people have personal biases they don’t recognize. People don’t always see the benefits of their gender, skin color or class. They may act in ways that support racist systems without realizing it.
The training classes Trump has banned are meant to help people be more aware of their biases and how they affect others. They are often used by corporations to train their workforces about diversity and cooperation.