errr... so anything related to UGC now has a lower bound of 3-4 FTE? Sure, I'll hire a team of content moderators next time I think about putting a comment form under my blog...
Please read their last sentence again and think about how much it understates the difference between stack overflow in its prime and a normal website. Also the "much of which still needs to be done".
Yes? Cloudflare doesn't replace moderators. At all. It only allegedly filters bot generated content, it doesn't filter user generated content and doesn't even intend to.