While the SE network is mostly in English, the community is made up of people from all over the world, a majority of whom are not native English speakers.
It is always a struggle to learn a foreign language, and the quality of education and lessons received, if any, can vary wildly between countries, or even within the same country. Not to mention between people because we do not all have the same capability to understand and learn a new language. Some people will be so fluent as to pass as native speakers, while others will struggle and stumble on every word.
There is also the fact that many non-US users will be unaware of the whole controversy on neopronouns, nor will they even know of their existence. Or, maybe, gender-neutral is a concept alien to their native language, and they struggle with it.
I expect many people to stumble when trying to use neopronouns. I expect people to edit posts in good faith to remove neopronouns because they are unaware of what the word is and think it is a typo or a mistake, which will bring a lot of additional work to our moderators.
I would ask that SE keep this in mind when handing out the rules explaining to mods how to deal with violations of the new CoC regarding pronouns usage so as to not penalize users who are not native English speakers.