Now, take that model and apply a really crude analysis. You would conclude that there is five times more crime in the more heavily patrolled neighborhood. Your algorithm, applied to policy, suggests that crime could be controlled better by patrolling the "bad" neighborhood ten times as much, rather than five times as much.
Now, consider the social result. The "high crime neighborhood" then sees its property values drop, and more homes sold into the rental market. This attracts poorer, rougher people who can't afford the "good" neighborhood. Now crime actually goes up, reinforcing the idea that the bad neighborhood is high-crime.
Now, imagine we've been doing this to those two neighborhoods for generations. What are the likely results of your algorithm? There's your uncomfortable truth.