It happens in many different contexts and often I feel there's a logic to it. Lots of people who are marginalized in one way are privileged in another. Maintaining access to that privilege can also mean an expectation to maintain your own marginalization. If someone feels they end up better on the whole by doing so, and isn't deeply connected to others without that privilege, and doesn't feel safe navigating life without that privilege, it gets pretty easy to justify on a personal level.