The Taliban believed they could get rid of sin, by being brutal to anybody who didn't obey the law. This did not lead to a moral society, just a terrified one. Not of God's wrath, but the guy next door about to reporth him to the authorities.
It is actually one of the fundamental reasons why I believe that pedophiles should not be released from jail for good behaviour.
If your sin is being sexually attracted to 4 year old girls and acting upon it, you are not "exhibiting good behaviour" in prison by not molesting the non existant 4 year olds that you have access to in jail. I believe that spiritually we are in the same boat. Set up a theocracy and we are the equivalent of that man. We can't sin, we desperately want to do so, but aren't given free access. There is no morality there, no spirituality, just terror and lack of options.
Banning consentual behaviour in adults does not make us better, doesn't save our soul, it makes us afraid of Rome, not of God.
If you are alone on a desert island, and you don't commit fornication, all the power to you, it doesn't test you one bit though.
If you walk through a street with strip bars on your way home, and ignore the temptation, it redeems your faith and strengthens it.
Whether any consensual sexual activity between adults has harmful effects on society as a whole is very much open to question. That's what we have legislatures for.