That is a great article, but I take issue with the analogy between ex-con criminology professors and “pedophiles . . . operating day care centers and rapists . . . counseling battered women.”
There’s a difference between studying something and working directly with potential victims. In some cases, someone who’s done something has unique insight (for example, a lot of researchers into homosexuality are themselves homosexual), but it’s never a good idea to put a predator right next to his prey.
Therefore, a criminal criminologist is akin to a pedophile sexologist, not a pedophile day-care worker. A “pedophile at a day-care center” analogy more suitably applies to a criminal who works as a police officer or locksmith, where they’re not studying crime but basking in crime opportunities.
But of course, the basic argument holds up: You don’t need to engage in something to study it, and when the topic is crime, doing so is kind of a problem.