Correct. It implies there is a correct way to be and that correct way must includes both or it does not count for either.
If you are heteronormative and polygamous, you are not heteronormative .
If you are homosexual or otherwise other-than-heteronormative and monogamous, you are not monogamous because it only “really counts” when you are in a heteronormative relationship.
Here’s some other quotes. She is very good at this.