I do think there’s also a difference between what we faithful in the pews would like or expect, and what is necessarily possible today.
People forget that this isn’t the Middle Ages, where religious vows may have had some force of law. In the secular world, being a priest or a religious is treated as essentially a job, choosing to work for a Nonprofit and possibly having some unusual pay or living arrangements. A priest can leave or quit at any time.
In other words, if a priest goes bad and decides to do something immoral, the superior is obviously going to have to handle the situation as best he can, balancing help for the victim, prevention of further evil, and if possible, help for the priest. If clerics are not being ruthlessly handed over to the secular arm (as it used to be referred to in the Middle Ages when a person was convicted in a church court and then given to the government for sentencing and punishment), it’s probably because the superiors recognize that the guilty priest will not have much shot at repentance and saving their soul in a modern jail. About all that can be reasonably expected is that if crimes were committed and the superior (employer) finds out, he report those crimes to the police. If a priest has done something that’s abhorrent (to a Catholic) but not illegal, most superiors would probably not choose to immediately defrock or expel, because then you lose control of the bad apple. Assuming you are even sure he did it. Better to transfer him somewhere else where hopefully he can’t continue his bad behavior. But that probably means not telling people about your suspicions, except on a need-to-know basis.
Every “bad priest” is going to be a different case. Is he a serial pederast who has for sure been sɛҳuąƖly abusing prepubescent boys? Is he an otherwise blameless and exemplary priest who has a couple of accusations or insinuations against him? “Investigation” may not be straightforward either. You don’t want to tell people the rumors unnecessarily, nor alert the man under suspicion and give him more cause to hide evidence. Was he caught having an affair with a woman? Or saying inappropriate things to an adult parishioner? All these things would probably require a different course of action. And you could sentence a priest to some kind of no-contact-with-faithful “rehab,” but there’s no guarantee he won’t just quit his order. We should not be surprised that these things are kept pretty secret. It’s not just to “protect the Church’s image.” I imagine there’s very few cases where a superior has absolute proof that a priest is guilty of crimes and can say “Ok, see, we are very transparent and hate sodomy, we caught this one abusing altar boys and now we are handing him over to the cops. Hopefully the state will execute the monster. May God have mercy on his soul.” As satisfying as that would be for everyone.