The community was the ones moderating the content in its entirety (with a very small fraction of that moderation being done by the mods - the ones with a diamond after their name... after all, they're part of the community too). Community moderation of content was crowdsourced.
However, the failing was that not enough of the community was doing that moderation.
https://meta.stackoverflow.com/questions/432658/2024-a-year-...
Note the "Questions closed" and "Questions reopened".
Compare this to https://meta.stackoverflow.com/questions/340815/2016-a-year-...
The tools that diamond (elected) moderators had was the "make the site friendly" by removing comments and banning users.
The "some of the answers should have been deleted" ran counter to the mod (diamond mod this time https://meta.stackoverflow.com/q/268369 has some examples of this policy being described) policy that all content - every attempt at answering a question - is valid and should remain.