MsBeaujangles
Whilst I agree that non binary is an accurate description of many people, the problem starts occurring when it is assigned rights.
Assigning rights based on a feeling that is objectively unidentifiable and non-verifiable can't possibly work.
Which is how we have seen the issue of self identification explode. It's based purely on what someone says.
An interesting one would be to make gender nonconformity the protected characteristic. So you can't be fired for it, denied housing, medical care, anything - on the basis of it.
But, at the same time, you don't get ceded rights from other protected characteristics like a woman's sex.
It would mean anyone, trans-, agender, femme, non-binary, bitch women, effeminate men, could all be included under the term gender nonconforming.
I haven't heard a downside to that concept. There probably is one, but I can't think of it!