The death penalty is one finger in the hand that builds civilization, Tim.
One time Caesar was kidnapped by pirates and ransomed. He told them to charge high because he would go back there to kill them all (they thought he was mocking with fake bravado), and so he did, including any women and children who offered resistance. What few survivors remained he sold into slavery.
Later Romans promised to eliminate piracy from the Mediterranean, and so they did, by going to each pirate tribal people and exterminating them and selling survivors into slavery.
By the 10th century, Venice was under extortion from a tribe of brutes, the tribute would run for another 50 years. Instead of making generations of Venetians pay for protection from criminals, a new Doge decided to invest the money in an army and navy and destroy their oppressors. He did so, attacking by surprise. History records: "no one heard of those people ever again since then". They used to be known as Paganians because they were the only society in the region who did not convert to Christianity.
We need to remove violent sociopaths from society so the rest of us can be free, trust each other, leave doors and cars unlocked as people used to do in 1970, not that far away... People used to hitch-hike, kids used to go and come from school by themselves, nobody was afraid of pedophiles, children could be free... How quickly countries go to shit when pro-crime leftists take power...