It is quite literally just thinking critically . . . but particularly, thinking critically about things with respect to their racial components.

Let's say I am writing rules for your neighborhood's homeowner's association and I say "People who dye their hair are odd. We don't want odd people owning homes in our neighborhood, so you can only sell the houses here to people with natural blonde hair."

If you say, wait a second, this rule is overly broad, this rule as written does not just prevent homes from being sold to people who dye their hair, it sweeps up everybody who does not have natural blonde hair, which means people from many different races would be prohibited entirely from owning a home here--then congrats, you just participated in Critical Race Theory. You thought "critically" about how a policy might have a disparate impact on people because of their race.

Ask yourself why anybody would be opposed to critical thinking, whether it's about race, gender, or anything else.