While I would personally wager that those in prison are on average less moral, there was nonetheless a valid point above that those who commit crimes don't necessarily lack morality. The argument here would be that law does not perfectly equate to morality, and separately, that people will commit crimes out of the lesser of two evils in some given scenarios.

Additionally, despite the reasonable conclusion we can make that those in prison are less moral, it probably does no good for recidivism rates for us to talk about how immoral prisoners must be. It stigmatizes them, and puts more barriers on the path to recovery and reintegration into society.