So you want a criminal to be whacked for killing other criminals? That makes you no different than those criminals. Personally I don't have a problem with a criminal killing other criminals. It's their business, why would you care about it? It's not like Saddam Hussein ordering a chemical attack on innocent women and children.
He also sells drugs and extorts, as far as I know, and it's not like every single one he whacked 100% deserved death, not all criminals warrant a death sentence.