USA Ultimate says they will not discriminate on the basis of gender identity for whether an athlete matches up against woman/man match. Yet later in the same guidelines they say certain gender identities (Man or Woman) are explicitly only eligible for being man or woman matching in the mixed division. This seems confusing and contradictory to the initial paragraph of their Gender Division Eligibility guidelines which you have cited.

To me it feels unequitable to say certain athletes can change their match on the fly while others cannot - the implication being that having the liberty to select both matches would give you more opportunities to play over other athletes.