Is it my imagination, or is there a group here that appear to get their jollies by disciplining their children?

Yes, apparently some adults experience a sexual thrill when they beat children, their own or others. Many years ago, around the time of the Rodney King beating (look it up on Wikipedia if you're too young to know about this), there was a lot of attention on the brutality of the Los Angeles Police Department. It came out that one of the sub-chiefs (I can't remember his name) had given a sermon at a church where he talked about beating children with oars until their skin welted, and how thrilling this was.