Had a bishop who was a holy old guy who believed in giving priests a second chance. He famously ran an advertisement in the NCR inviting them in. Brought a few good ones to the diocese, along with a number of predators. This was in the seventies and eighties. I can accuse him of naive stupidity, but I cannot accuse him of criminal neglect. As for why it was all so hush-hush? Canon Law, 1917 version, commanded bishops to keep such things quiet to avoid scandal. Well, that didn't work so well.