The job of the moderators is to ensure a safe community, not to enforce things “related to NixOS specifically”, so I don’t understand where this question comes from.
More broadly: something that seems to be getting lost in the discussion here is that community management is a specialization. It is a skill, and one that is particularly difficult to learn. If you are not an experienced community moderator (and merely “having a mod flag” doesn’t qualify for that), then you are almost certainly going to see moderation decisions that you do not understand, because they are the result of years of expertise and learning about behavioural patterns, something that people don’t typically do outside of community management jobs.
Now of course it’s understandable to want to understand how a certain moderation decision was arrived at, and it’s certainly possible for moderators to make mistakes - they are people and therefore fallible like everyone else. Having an inquiring conversation about moderation rationales is thus reasonable.
However. It is not reasonable to assume by default that if you, personally, do not understand a moderation decision, then it must be wrong unless proven otherwise. You wouldn’t assume a carpenter to be wrong just because you don’t understand their techniques; so why would you do that with a moderator?
And yet, that is what very often happens, and it is what happens here too. People could privately reach out to moderators, and ask them to explain the moderation decision, and that would be fine. But aggressively demanding explanations while implying that it must be an invalid ban because you don’t personally see the reason is something entirely different, and very much out of line.
Part of this expertise of community management also means realizing that a “legalistic approach” to moderation (“it’s only bannable if it’s in the rules”) does not work, for the simple reason that moderation fundamentally involves dealing with bad-faith users at times. That doesn’t mean that all moderation is against bad-faith users, but some of it always will be. And bad-faith users will rule-lawyer, because their goal is to find a way to be an asshole that Technically Complies with the rules, but violates their spirit.
In other words: a moderation team that strictly implements a set of community rules (whether you call them “rules”, “code of conduct”, or anything else) just cannot do their job. This is where the subjective judgment of moderators comes into the picture; their job is to keep the community safe, not to enforce rules. If something is creating an unsafe environment, then it is their job to do something about that, regardless of what the rules say.