It was Knorr who began pushing the 'issue' in the 1950s. He was truly victorian in his attitude toward sex (the scuttlebutt was that he never consummated his marriage), and probably had a 'problem' with masturbation of his own. Hence, he was fanatical about it in print, probably wanting to absolve his guilt in this whacked out way. Knorr grew up in a time when a good many religious people thought that masturbation was a horrible thing, and obviously this cultural view rubbed on him. Pun intended.
A former District Overseer who had been one of Knorr's favorites in Bethel in the 1950s told me that when enough new "Bethel boys" had accumulated, Knorr would haul them into a locked room and give them his anti-masturbation lecture. "When you're urinating, make sure you don't touch 'it'," he reportedly said. Touching 'it' apparently could lead to terribly sexual thoughts. What a sicko!
AlanF