Two concepts that don't fit all that well together are defined as being the same thing. One of the concepts is a category of people. The other is an action that is considered bad, or a target (person or category of people) defined as those people who do that bad thing.
For example, a preacher who want to paint gay people in a bad light may fight for a discourse where unprotected sex with strangers is included in the very definition of homosexuality. Either that, or simply use a concept of “sexual deviation” where homosexuality, pedophilia and self-destructive forms of promiscuity are defined as being inherently the same concept.
Included in many forms of guilt by association.
This is an abstraction of categorism.