Yeah... I heard that too, about half a year after I got really into nix.

To be honest, I try to keep away from community drama as much as possible, so I am not entirely up to date here. I think (and I might be wrong, if someone reading this knows better, correct me!) there's three main points of contention:

• Queer, PoC, and other "minority" users experienced harassment on (semi-)official channels (Github, Discord, Forums): That fucking sucks. I'm queer myself and lucky enough to not have experienced any of that in my time with Nix, but if I had not decided on Nix yet and learned about this before getting invested, it might have given me enough pause to not put any time into this. In all honesty however, that's sadly a problem with many, many OSS projects.
• Governance and Funding: I do not know much about the governance, afaik there was a bit of drama about the inventor of Nix acting like a (benevolent?) dictator for life, but those issues should have been resolved with a new governance model. The really big, inciting incident of a lot of community drama with Nix through was a bit over a year ago, when the committee in question decided to let Anduril fund a NixCon, against the explicit and loud protests of the community. That sucked. Hard. While obviously all kind of shit companies use all sorts of great OSS projects, inviting Anduril to sponsor your official conference is.... not really understandable.
• Conflicts of Interest: the aforementioned inventor of Nix owns a company heavily invested in the nix ecosystem. A bit reminiscent of the way that, say, Google holds Chromium by the balls, though to a much less severe extent. Miraculously, features that are "extremely unstable" in nix (but wanted by the community for a long time) suddenly get released in closed source to enterprise customers.... However, the open source project is separate from, and not beholden to the whims of, said company.

My position on all three points is this: They are not great; but a) they do not threaten the ecosystem, which is mature and independent of this drama, and not reliant on one or a couple of central, potentially problematic, people; and b) there are community projects that actively and effectively do distance themselves from all of these points (namely: Lix) and which are drop-in replacements for the core nix language and compiler, meaning if the upstream project actively did something to really piss you of, you could move with very little work to something independent of Nix.

I hope this will not become necessary, because Nix is genuinely magic. Once you get the hang of it, nothing on your computer is particularly difficult anymore. You also get the best-in-class package management (and it's easy! Once you have configured your own system to your liking, you already know everything you need to package your own software and contribute to nixpkgs!), being "bleeding edge" yet at the same time incredibly stable (seriously, I have switched all of my servers and VMs to Nix and I have not had one single incident once, including after updating machines after forgetting about them for 1.5+ years).

Anyways. Sorry for the wall of text lol.