The original poster made two categories: Engineers and Moderators.
Engineers? Definitely years of training and education...
Moderators? What education is required to say "Does this post break community standards? (Check yes/no)"
It doesn't, but the potential trauma and psychological damage they might get from this kind of work should put it in the "high risk, high reward" category. I would never do a job like that knowing it could scar me for life unless the rewards were fantastic in that moment. And I believe that most people, knowing what this job entails, would say the same thing.
The way the article puts it, these moderation companies are looking for whoever they can to fill the chairs in order to meet their quotas, offering a seemingly larger paycheck for what they advertise as an easy job. They literally mislead people so they accept this job, and when the hired person finds out what it is really about, they are likely to be dependent on that income and can't leave the job. And as time goes, they get more and more damaged, to the point that the company eventually fires them, and they are left with no money, no psychological help and traumatized for who knows how long.