How does 4chan do it? Last I checked they have moderators (well "janitors"). They are volunteers, work for almost no recognition (still Anon), and probably do not have the mental health problems that regular people do.

There is also clearly an ability to follow direction or enforce appropriate (e.g. the janitors of /b/ /pol/ /g/ and /fit/ are clearly all operating on different sets of rules).

I am 100% in agreement that you cannot hire an army of temps off the street and tell them to moderate the internet, but it's clearly not something beyond human capability. You just have to be hiring in the right places.