"Honour" is quite a vague abstraction, though, and romantic too. It's not beneficial, historically, to categorise anybody - be it Napoleon or a neighbourhood thug - as either honourable or a dirtbag. There's no real worth in that kind of thinking.

Crime isn't a product of individual will; it's a social problem. It's quite embarrassing to have to point out that organised crime - that under which the Mafia falls - seeks organisation, a collective harmony (its hierarchy, its rules, its secrecy; all of these result in notions/misconceptions of 'honour') that allows it to operate as a fully functional organism. And it's criminal not only because it's against the law, but because its fundamental operations, which it requires in order to function, are set up so as to gain wealth at the expense of other people.

If the historian is to be of any use, the Mafia must be studied as a major aspect of social crime.