This seems to be a case of one person who's said some things that pretty much everyone would regard as inappropriate and potentially offensive (probably regardless of where they stand on CoCs or their views regarding identity politics). I see no evidence of a connection between this person and the resignation of the Rust Moderation Team.
I'd also add that making white men feel unwelcome in an open source software project is very hard work. I am a white man, and would not for a moment feel uncomfortable about trying to contribute to node or Rust because of the indelicate mode of expression of this one individual.
If the core team took her side even though she said those inappropriate and offensive things then it makes sense that the Rust Moderation team felt that they couldn't do their job and resigned because of it. Note that she is a part of the core team.
As you can see this sub thread is just speculation from the first post. The evidence are the links provided in the posts above and the rest is speculation how that could potentially related to what happened today.
I'd also add that making white men feel unwelcome in an open source software project is very hard work. I am a white man, and would not for a moment feel uncomfortable about trying to contribute to node or Rust because of the indelicate mode of expression of this one individual.