When much younger, I remember attending many local races where there were no divisions. Everyone started at the same time and competed against everyone else. The first three finishers received recognition and awards.
Some race directors started adding a separate category for female runners. I have also seen categories for walkers, all sorts of age groups, those with physical disabilities, those with intellectual disabilities, those running with dogs, athenas and clydesdales (those that weighed a certain amount more than average), local resident categories, club member categories, those pushing babies in stroller devices, those running with their child, those running with a spouse, those running in a costume, etc.
Now some event directors may choose to expand their categories to include those that identify as nonbinary. There are numerouss other catefoties that could be added based upon how individuals choose to identify themselves.
I have no preference about what categories event directors choose to offer. I a Event directors have the ability to offer as many or as few divisions as they wish. (I have also attended races where there were no categories, and even the runner that finished first was not recognized) Runners can decide what they are and what they want to be, based on genetics and/or their choice, and enter any category that they wish. Participants can also choose not to select any category, and refuse to provide information regarding their gender and age that are on most entry forms.
If I do not like what categories and event offers, I do not have to participate.
Events directors do not even have to separate categories when they recognize participants. It would be intersting to see someone get awards for finishing third overall running as a nonbinary individual in a team with their spouse in the 20-29 age group as a local club member and heavier runner with a phycical disability in a costume.