I'm immediately put in mind of <PERSON> "Discworld" series. It's a tongue-in-cheek parody but the ruler of the main city has simply incorporated things like the Assassin's Guild and Thief's Guild into the civil government.
His reasoning, in a nutshell, is that you are going to have criminal elements anyway so you might as well put them where you can see them and give them some rules that they can follow. The Thief's Guild actually becomes responsible for all theft that occurs in the city. There are quotas and buyout options, effectively making the Thief's Guild into an actual, functional "protection racket". If you have paid your fee and someone robs your store, the robber will find that not only are the cops after him, but so is the thief's guild, and generally it's better for him if the cops find him first.
The Assassin's Guild works much the same way. Assassination, for a suitable fee, is accepted, however, the Assassin's Guild is held responsible for all murders that occur in the city. 805
Unsanctioned murder is, therefore, going to be a case of who catches you first: the cops or the Assassin's Guild.
Like I said, all a very tongue-in-cheek parody but there is a logic to it and maybe the scientist in question had the same thinking, or maybe that's similar to how things work now. Maybe the criminal classes even come with a code of conduct, such that an assassin gets assassin skills but he also finds that he must be paid to kill, and must feel it is a fair value. Assassin classes never become psychopaths or plain murderers because they are programmed against it. They might even find that their programming makes them feel personally affronted to hear about an unpaid murder. Net result: there are still assassinations but "random crime" is actually tapped down with vigor by these programmed criminals.
Alternatively, I am also put in mind of <PERSON> character in Fifth Element, where basically he felt that destruction was necessary for a productive society.
The Matrix had very similar reasoning, too. The machines found out that utopias didn't work. They created a realistic setting, crime and all, because it's what humans seemed to expect and work best in. 44