Is it due to murder lacking suffering? The worst crime is not the crime I believe should be punished hardest. This is an important distinction in my mind. Some people are probably beyond rehabilitation.

I do believe torture should lead to harsher punishments. Depending on several factors.

How much torture is enough to warrent it being worse than killing? What about domestic violence? The latter often being inflicting a significant amount of harm and pain on an individual over long periods.

What about long term harm done through serious neglect?