Found this blog post and found it had more insight into the issues around the dev and the toxicity in FOSS
The guy is German, and the German language traditionally uses generic masculine pronouns, although that has become a big political issue in the past years. Some new gender-neutral forms have developed, but some of them have even been banned by the “center”-right-wing clowns in two state governments, and it’s all a bit of a mess. The guy probably thoght “they” in English is a similarly experimental concept, and while it’s still dumb and he should just try to be as inclusive as possible, it’s probably not a matter of him purposefully excluding women from the documentation.
That makes more sense i guess, although even with that context as you said, it is still dumb. It’s political in the US as well to use non gendered pronouns. It’s generally aimed at hurting trans folks more than anything or anyone else. I could see the first time having it be a flippant meh response, but multiple times? Having had it explained clearly? Someone else has however said it has been fixed now. People can change, so my current plan is to assume things are better, cautiously, and hope they continue on a more pleasant path.