Doesn't look like they're planning to dictate that, any more than spellchecker dictates how you're allowed to spell things.

Yes, but the implication is that if you don't use the suggestions you are evil.

If you type "teh" and refuse to correct it to "the", people will just say you're wrong. But progressives have started to frame everything as being either good or evil. (This used to be the domain of the religious right.) So if you stick to "landlord", you don't have a classic opinion on spelling, instead you're denying "landnonbinary's" right to exist.

Something like this happened 8 years ago when a maintainer refused a merge request to replace "he" with "them" in libuv because he thought it was a valueless change. He was destroyed because of it. https://github.com/joyent/libuv/pull/1015

I believe this side of the debate is way too exaggerated. I really dislike this language policing, but slippery slope is a logical fallacy for a reason.

They will by setting a trend and pushing people to think in a certain way.