You see priests molesting kids, lay ministers molesting kids, and you see bishops ignoring them, transferring them, and the pope not doing a damn thing about it. And this goes on for almost thirty years. Little by little, you no longer believe very much. And then something happens, and you snap, and realize that these creeps will NEVER, EVER get your family again.
And you leave.
As an epilogue - the latest pervert in our saga was finally kicked out of the parish eight years after we left. He was a lay minister. Whether or not he is at some other church in the diocese, I don't know.
So if you "saw" all of this, and knew things about it others didn't, and if laws were being broken, did you go to the police? Did you, personally, go to the bishop with evidence in hand?
I would not hesitate to report a molesting priest to the police, if I thought laws were being broken. I'd report him to the police before I reported him to the bishop, in fact.