[inputvolch]

Education is like a sewer? No matter what I put into a sewer, my guess is that it's going to come out covered in shit.

[lisper]

It is an allusion to an old joke. Here is the original source: https://youtu.be/w8d0GwzY6cA?t=2210

[dkarl]

Maybe the point is that what you get out of it depends a great deal on what everybody around you puts into it, a depressing fact that online learning can hopefully mitigate at least a little bit for people who have access to it.