Are all inmates deranged killers? No. Lots of crime like fraud or deception being committed too. You can be jailed for refusing to pay council tax. Many inside are victims themselves.
Stephen Fry has served time.
Other than removing criminals from wider society, prison serves little other useful purpose imo. They are breeding grounds for further criminality both before and following release.
A minorty of offenders are a simply a menace to others and dangerous and need to be removed from society until they cease to be so. For the rest, imprisonment should be a last resort, when all other means have failed. Technological advancements will see the form and substance of criminal punishment change in the next generation imo. It will involve a further ratcheting up of the surveillance society we live in, but I expect derivation of liberty for most offenders will mean something very different in a couple of decades, with home curfews and work in the community being the norm.
I believe the issue relating to drugs will be addressed in that time too imo. The current legal position simply isn't working and needs to be looked at in a forthright and honest fashion.
Your parents were soft, I gotAgree entirely GDM. But I only have to look to a crime and punishment analogy from my generation to my children's for evidence of this.
When I was being punished for some minor indiscretion (usually smoking and / or drinking) I was grounded and cut off from my friends.
Now, as a parent, when I need to enforce acceptable boundaries with my children I cut them off from their friends my confiscating their mobiles / tablets / Internet access.
Society will do similar and fit the punishment to the crime. Prison does, in my view, cause more harm than good for certain personalities and simply facilitates increasingly unacceptable behaviours.
Your parents were soft, I got
Flat of a knife across the back of the legs
Nettles across the back of the legs
Wooden spoon round the head
Belt
In that order.