Stack Exchange is based on a very simple premise:
Eliminate the problems with online forums by removing those things that detract from the site's singular purpose, which is to provide fast and quality answers to people's questions about a specific topic area.
Stack Overflow mods are (in theory) elected on the basis of how well they can fulfill this singular premise. The moderator position was never meant to fulfill political expectations or satisfy everyone's sensibilities about how the site should be run. That's one reason moderators are elected for life: so that they don't have to succumb to arbitrary and capricious pressures from the user community.
Rather, the position was created to fill a void: step in when the community is unable to resolve disputes on their own. It follows that, for the most part, the communities should be able to run themselves, and moderators should step in only when needed.
To achieve the premise outlined above, Stack Exchange created a framework, some software and a set of conditions and rules that govern the way all Stack Exchange sites work. This framework includes a self-moderation mechanism that allows users with experience to vote on posts, cast close and delete votes, and engage in editing. These tools allow the user community to curate content, which means that, by necessity, the content that is least useful eventually gets removed.
Within that framework, moderators and the user community must exercise their judgement. Which content is useful, and which content isn't? For the most part, the quality and character of that judgement is what moderators campaign on, and how the user community decides who gets elected.
This approach does not come without a degree of controversy. There is no shortage of posts on the Internet accusing Stack Overflow of being an elitist club, mostly from new users whose vague, underspecified questions get closed; and to be fair, the veteran user community has been more snarky about this than they should have been.1 This was the motivation for the "Be Nice" policy, a policy that I wholeheartedly endorse.
This was the status quo at Stack Exchange for many years, until the "Welcome Wagon" came along. Suddenly, it was no longer about curating content; it was about being welcoming to everyone who visits the site. The veteran user community, long used to being called elitist by new users who couldn't bother to form a complete sentence in their posts, was re-cast as the enemy of inclusion.
Have you noticed that I haven't used the word "culture" even once yet? That's because the community genuinely couldn't care less what your background is, so long as you know how to ask a good question.
So do the moderators accurately reflect a cross-section of the user community? New users whose questions routinely get closed represent a significant percentage of the user population. What do they want? They want their questions to stay open. Do we represent their wants? What happens to site quality if we simply acquiesce and give them what they want?
The job of a moderator, at least until recently, was a very simple one. Remove anything that detracts from the singular goal of getting good answers to good questions. You don't need a survey or a form or a new CoC or any special considerations from anyone to fulfill that promise.
Stack Exchange, as a platform, was never designed to do what we're trying to get it to do now. "Learn the ways of the platform" and "Be nice to others" was always good enough.
1Although it is not an excuse, in their defense, the users who take it upon themselves to improve site quality by undertaking curation duties are vastly outnumbered by the number of new users who haven't figured out how to ask a good question. Many people don't know this, but Stack Overflow actually has an automated filter, similar to the Bayesian filters used in email systems, that removes the worst of the worst posts before they ever get to the front page. I don't remember exactly what percentage of posts are blocked this way, but it is significant; somewhere between 15 and 35 percent of all new posting attempts are blocked, IIRC.