Common meaning:

Belief of a few people that those who have white skin are superior to other racial groups.

Hidden meaning of the Equity religion: 

Belief that all of Western liberalism is a front for white supremacy.

Discussion:

The Equityists believe that the entire Western world was created by white people to benefit only them. They created the lie that white people are superior in order to keep other people oppressed.

Equity says that there are not just a few small groups that promote white supremacy, but that the entire system of Western liberalism is white supremacy to its core and must be destroyed.

White supremacy is an illusion created by Equity activists in order to bring about their agenda.