One lesson I've learned from 10 years using Stack Overflow is that its moderation is obnoxious. Eventually, in 2013 I started jotting down links to questions that were closed despite being well-written questions with thoughtful answers, whenever I encountered one in the normal course of my day to day work. I'm well past 20 at this point. And that's not counting the Serverfault article I just saw the other day where a user had a question about compiling php (a technical question that received a correct answer). The question was closed for being off-topic. Compiling web server software is apparently off topic on a site for system administrators, confirmed by multiple mods.

Stack Overflow's content is good because:

1. The site design is high-quality.

2. The users are high-quality, and early on received a lot of positive encouragement to ask good questions and provide good answers.

The site does not need much moderation, possibly apart from cleaning spam, harassment, other blatant violations of site policy, or possibly duplicate questions (mods should have the decency to actually read and understand similar questions before closing as dupes). The idea that closing stuff like "A vs B" comparison questions improves the site is just hogwash. The reason "A v B" comparisons on SO don't devolve into fact-free opinionated bloviating on SO is because (a) the site is so rigorously designed to encourage quality posts and (b) early on they attracted a large and serious userbase devoted to making high-quality contribution. Mods have nothing to do with it.