That is besides the point. Languages are tools of communication, and you and your circles are using it however you want, which is how languages evolve over time. They are calling it a wrong use of the English language, and telling their opinions why they think so. That is a linguistic argument. Having differing opinions about what is a correct use of words, does not fit the definitions of “gatekeeping”, as you are not prevented from using English the way you want to. If your use of words is not being understood or is refused to be used by others, that is not preventing you from doing. It is a failure of communication.

“I refuse to use it because It is harder” is not an argument, that I have made. What I have pointed out is, that it is especially hard to get people to use neopronouns, since they break the commonly accepted English grammar. The difficulties stemming for example from discrimination, are only one of the issues, that affect people’s opinion about their usage. Ignoring that and claiming it is all because of discrimination or gatekeeping, is either misunderstanding the arguments, or resorting to ad hominem.