Speaking as someone who has to deal with supervised learning models, human beings falsely tag positive examples as negative all the time. Merely having "average

Speaking as someone who has to deal with supervised learning models, human beings falsely tag positive examples as negative all the time. Merely having "average" human beings tag examples doesn't guarantee perfect recall. Or to restate, sites that rely purely on manual moderation of content that breaks rules still has content that breaks rules leak through all the time.