Clarity and comprehensibility versus a person's right to define what their gender identity is.
But what if the subject is not a single individual but a group of people defined by their nationality or by their occupation? Should Stack Exchange always embrace the usage of neopronouns, and should it always respect a user's choice of words as long as that neopronoun is inoffensive?
Across the entire Stack Exchange network, many users, unfamiliar with the pronoun FAQ and the recent changes in the CoC, will see what they think is a typo and "fix" it. By approving the suggested edit (themselves) proposed by the editor–which in my view was perfectly legitimate–there was the risk of initiating an edit war between the editor and the author of the post.
On the one hand, it's easy to mistake a neopronoun for a spelling error and suggest an edit. When edit is carried out or approved of, the author of the original post might feel hurt, annoyed, or offended. In search of validation, they could flag the edit and accuse the editor of being disrespectful or, worse still, unwelcoming. How should a moderator react to such a flag? Ignore it? Decline it with a boilerplate message? I think not. In the aftermath of Monica Cellio's demodding, that option is no longer available. The moderator will either have to rollback the edit or explain why that neopronoun was unacceptable....
Whereas if the author simply chose to remain silent, the editor would be unaware that their edit hurt that author's feelings or was unfavourably received and (perhaps) continue editing out any neopronouns in the future, oblivious to the storm that is brewing in the background.
Am I blowing this out of proportion? No, I don't think I am because recently, someone suggested that an edit of mine could be viewed as being unwelcoming and that simple spelling fix, which by the way was totally unrelated to neopronouns, may have contributed to the newcomer's impression that the site was unfriendly and spurred them to delete their question.
In all likelihood, we're going to see an increasing number of similar episodes in the future, as seen in @Glorfindel's cool-headed answer as well. Unfortunately, offending someone's sensibilities has become a minefield of late. No one is exempt.
Some Stack Exchange sites will be affected more than others, but on social media it seems there is a growing movement of vocal LGBTQ+ supporters who use their platform to criticise a celebrity's Tweet (etc.) by employing the slurs; homophobic, transphobic, or TERF, accusations which were also posted in comments and in posts last year. Unfortunately, this trend will continue to spread if the Stack Exchange management does not provide clear unequivocal guidelines to their volunteer moderators. It is not enough to say in the CoC
Use stated pronouns (when known). When in doubt, don't use language that might offend or alienate.
I would hope that moderators will be provided with more substantial assistance and training.
In contrast, I do believe the reasons for rejecting the edit was done in absolute good faith, the intention was to respect the voice of the OP. But it must be pointed out that the suggested edit–themselves–is completely gender-free. There is no one sex or gender associated with they, them and themselves. The editor could have suggested the singular themself, although that probably opens another can of worms.
A typical American would consider themself a sports fan
I use the pronoun themself quite happily myself but purists will object, leading to new discussions. Generally speaking, users and native speakers alike, remain largely unaware of the existence of these neopronouns despite their somewhat long history.
One the earliest gender-free pronouns was coined by Michael Spivak as long ago as thirty years ago
In 1990, Michael Spivak used them in his manual, The Joy of TeX, so that no person in his examples had a specified gender. […] Many users enjoyed choosing pronouns that didn't specify their gender. The pronouns then became a common feature of other multi-user chats made throughout the 1990s.
The Spivak pronouns are the ones highlighted above: e, em, eir, eirs, emself
To sum up, like it or not, we all need patience and time to become accustomed to these new pronouns in the English language, it will not happen in the space of a year, it will take several. We are only at the beginning but the change is inevitable.