Napier said in an interview on BBC Radio 5 that paedophilia was "a psychological condition, a disorder".
He said there was a difference between committing a crime and being a victim.
"If I – as a normal being – choose to break the law, knowing that I'm breaking the law, then I think I need to be punished," he said.
"Now don't tell me that those people are criminally responsible like somebody who chooses to do something like [crime]. I don't think you can really take the position and say that person deserves to be punished. He was himself damaged."
The Catholic Church has been accused of going to great lengths to cover up the sexual allegations against its priests over the years.
Napier said it was a condition that needed to be dealt with.
"What do you do with disorders? You've got to try and put them right" – Sapa