Earlier quoted context omitted.
See, what you're saying makes some logical sense in a vacuum but it's so utterly unlike how any other website works that unless you take a huge amount of effort to explain this to people, gently , then it's not at all surprising that people just bounce off of it.
> but it's so utterly unlike how any other website works that unless you take a huge amount of effort to explain this to people, gently, then it's not at all surprising that people just bounce off of it. It is, and that's fine. It's incompatible with a site becoming large; and that, too, is fine. A large site was not required to accomplish any of Atwood or Spolsky's goals aside from perhaps making a profit off of ads…
> the explicit purpose and sole effect of closing a question is to prevent answers unless and until it is fixed
This is a decision I would question. What is it about a bad question that makes answers undesirable until the question itself is fixed? Especially when the judgement of such badness might be faulty (even if it's encouraged to bias towards leaving it open). Again, the answer may be the moderators doing the best with the tools their given (e.g. lacking good ways to otherwise surface the better questions to potential answers), but this is exactly the kind of issue I think tends to underlie SO's problems.
> The way that people talk about "toxicity" on Stack Overflow comes across like they think it was constantly full of insults and slurs
I don't get that impression. The perceived toxicity comes from a somewhat inscrutable set of rules and also apparently inconsistent enforcement which created a lot of frustration with the site. None of this requires that the moderation is even impolite. In fact, people can get more frustrated when a result they consider wildly unreasonable is delivered with a cordial tone. The trope of a saccharine sweet but utterly evil bureaucrat exists for a reason, and I think that is the kind of impression people who describe SO as toxic are describing, whatever the underlying cause (which is almost certainly not that a bunch of people spending their spare time moderating a site are just evil for the sake of it).
(And it's not unique to SO. Wikipedia has a lot of the same problems, though with different causes and attempts to solve them)