I found both sides rather aggressive to be honest. The implication that the use of "he" implies that the author assumes every user is male comes with an implied accusation of some form of misogyny.

No, it didn't. Go read the PR, it's extremely polite. I in fact, would challenge you to try and think of a more polite and less accusatory way of bringing up the same issue. I can't.

Furthermore, the "generic he" has also been acceptable English for centuries, and has only been starting to be phased out in the past few decades.

Yeah, you know what else has only been around for the past "few" decades? Literally every single computer and piece of software ever made, you know what literally none of them do? Refer to their users as "he".

You want to make it sound like it's a simple ESL mistake? That's fine you're welcome to believe that, but do you know how I respond to translation mistakes when I'm speaking a foreign language? I laugh and say oops, sorry, my mistake I'll fix that. I don't say "don't bring your politics into this".

I'm sorry but you are making up a fantasy to try and believe that the author wasn't being an explicit asshole.

I mean, the whole point is kind of that the problem is getting defensive rather than making a change.

That's the root of a lot of these problems. People are intimidated by 'wokeness' because they think that caring about how they affect other people means that if they have the wrong idea they're irredeemable. Clearly that isn't compatible with continuing to feel alright about themselves, so they become defensive and double down. But the reality is, if they'd just like, quit it with the callousness and cruelty they'd be eliminating the problem to begin with.

Lack of acknowledgement of there being an issue becomes the primary motivator for making the issue worse.

It's like becoming a hoarder because you're too embarrassed to acknowledge what a mess your house is to clean it. Rather than pick the trash up off the floor, they shout about how clean their house really is and how deluded we all are for talking about the smell.

I found both sides rather aggressive to be honest.

This was what I thought as well. The PR was a simple request that I thought wasn't political at all, just a matter of inclusion which I thought fit. Kling got aggressive thinking it was a political move or some shit then the rest piled on calling him names and such.

I think he just thought it was bringing politics into his project, I don't think he was taking any sides at all but people made up their minds. His silence is a bit concerning, probably ignoring it all but, whatever, It's his project.