They had a voting system. By having mods decide what was and what wasn't a 'good' question undermined the whole point of the voting system. Mods should use their powers to filter out hate/spam/trolling/egregiously off topic issues not determine relevance/usefulness. As others have pointed out SO was a site with great answers but awful for asking questions. This is why ChatGPT is eating SO for breakfast.

Even if a question was super similar to one that was previously asked has value in exactly that it might be phrased slightly better and be a closer match to what people were Googling.