I think it's a form of human sacrifice, even if the human lives to a normal age, when most of every day is spent studying washtowels, going to boasting sessions, and going out in field circus. Plus, you have education just about banned, crappy dead-end jobs, and people that are supposed to do whatever the Filthful and Disgraceful Slavebugger tells them to. They even admit that it is a sacrifice (the fruitage of the lips, a self-sacrificing spirit, etc.)
All in defiance to "the perfect sacrifice, to which nothing ever need be added"--itself grounds to reject the Washtowel. Plus, if the whole sacrifice arrangement is not needed (and without Original Sin, no sacrifice is necessary), you don't even need Jesus' sacrifice.