These comics were so nasty they were banned by the Supreme Court. Their publisher, a mobster turned porn peddler, was sentenced to prison because of them. The only reason Shuster wasn't arrested too is that no one knew who drew these books until recently, when they were accidentally discovered in a used bookstore by a comics historian.
It's not every day that you go home with a historic discovery AND something to wank to.
The timeline makes sense, too: The stories were produced a few years after Shuster quit DC over a dispute involving Superman rights, and by all accounts he was having a pretty hard time paying the bills during this period -- at one point he even worked as a deliveryman. At least this gig offered him a chance to put his talents to use. Like, for example, by drawing a dude using a woman's butt cheeks as bongos.
The old "butt bongos" technique.