No one is saying he can't be part of society, but would you really want him back in a position where he has power over people again? You wouldn't let a reformed child abuser work in a nursery. He needs to accept that his current career is no longer a viable option and find a new one.
I'm not saying they can go back into the same career. There are more facets to life than career.
They will be persecuted in their personal life for the rest of their lives if people recognise them even if the offence happened years ago. The courts and CJS have dealt with it, that should be the end of it.