"NixOS project" did not call anyone nazis, there was no "purge", this article is clickbait and ragebait. What one contributor, however prolific, says, doesn't represent the entire project (even though I somewhat agree with him here - there are sadly some bigots in the community).
Nobody forced Eelco (the founder of Nix) to "abdicate", but there was indeed pressure to step down as the de-facto BDFL put on him by various people. He's respected as an engineer, architect, maintainer and mentor, but his community management skills were perceived to be lacking, and there were other perceived issues in the community - which boiled down to the fact that a lot of contributors didn't feel like they could influence the direction of the project. Note that he's not expelled from the project in any way, he's still a maintainer of Nix itself, which AFAIU from my interactions with him is what interests him the most, and he's more or less happy to leave administrative/community stuff to other people.
Then began a process to establish a new governance structure. Currently, we're up to a stage where there's now formal community values and a new constitution for the project. There's an election happening right now, with all active contributors able to become candidates or vote (although the deadline for candidate nominations has passed, so now we can only vote).
Thanks! The documentation team is busy working on it right now :) You can check out https://nix.dev and https://wiki.nixos.org - both are relatively new. There are also lots of improvements in developer documentation for Nix and nixpkgs in the last year.