Politics is about perception, and whether or not a well-identified paper finds a causal link from bond policies to crime is kind of neither here nor there. His anecdotal evidence (gunfire within earshot, drug-dealing behind his house) suffices for him. It's really hard to argue with that kind of reasoning by pointing to abstractions, i.e. a statistical model.
Basically when I see even faint signs of folks' favoring more authoritarian policies (e.g. being "tough on crime,") I want us to notice those signs, and think hard about how to keep that instinct from getting a full head of steam.