'They' has always existed in the English language as plural or singular, context dependent. Hence it's natural transition into a pronoun. Non-native English speakers can be excused for using gendered pronouns because the problem isn't them not knowing and using it in the first place, it's them refusing to update the language after a reasonable explanation to do so.
People are brigading, sure, but it's such a simple change to make, one that only helps the world. So, yeah, fuck the devs honestly. Just accept the PR and move on, there was no need for any of this.