In todays society is punishment a capital offence?

It just seems to me that the more a person does ie rapists, murderers, pheodophiles ect, the more lenient the punishment they get! why are we turning so soft on hard and despicable crimes like this. How much IS a persons life worth these days when a child killer can get 6 months on the grounds of diminished responsability? What does that even mean? A childs life was taken brutally and savagely but because he was DRUNK and couldn’t remember the ‘offence’ The judge took pity and said i know you won’t do it again. I personally would have hung him from the nearest tree but i am only one person and possibly my opinion doesn’t count for anything. How about any of you good folk out there, have any thoughts on this?