It mocks diversity policies by presenting race as arbitrary and surface-level, rather than some deeply unchangeable thing that pervades every aspect of your being. Since diversity policies are a way to push back against judging people differently based on race (aka racism), mocking them is inherently supportive of racism.
And as the other commenter says, it also mocks trans people. By applying their language to something presented as arbitrary and surface-level.
And as the other commenter says, it also mocks trans people. By applying their language to something presented as arbitrary and surface-level.