Even then, there's still some argument to be made that drug cartel leaders are a product of their biological predispositions and of their circumstances. I agree that something has to be done with criminals in order for society to function, but I think people tend to be more sanctimonious on this subject than I'm comfortable with. In short, I think criminals either helpless in any effort to resist doing bad, or they aren't, and we should teach them how.
If they're mentally incapable of resisting their affinity for crime, then we should pity them and treat them with some dignity. I do think that they have to be kept separate from society for the most part, but the answer is not to let them rot in prison.
If they are capable of resisting an urge to commit crime, and are also open to being trained to do so, then we should treat them. If they're not willing, throwing them into prison and treating them like dirt isn't going to make it more likely.