I think that is the base assumption the authors believe their readers already hold. It's something that doesn't surprise anyone- there is no novelty in it, and

I think that is the base assumption the authors believe their readers already hold. It's something that doesn't surprise anyone- there is no novelty in it, and it's so matter of fact that we've been trying to address it for years. This article was worth writing because of the idea "going to prison causes so much trouble around you, it makes it more likely for people you know or your family to go to prison, too." That's a novel idea, not just because it may explain the reasons people go to jail, but because it indicates we might need to reanalyze our whole approach to criminal justice— ostensibly, we jail people not only as a punishment to them, but also as a way to protect or improve society at large. If sending people to jail causes more criminal behavior, our actions may be undermining our goals.