The page you linked has a large headline halfway through: "3. Police deter crime by increasing the perception that criminals will be caught and punished." "Ca

The page you linked has a large headline halfway through: "3. Police deter crime by increasing the perception that criminals will be caught and punished." "Caught and punished" is the important part here. The problem is that today there is effectively no punishment and no consequence for getting caught. In fact, the people who get caught go right back to the railroad tracks and do it again, and brag to the cops that their charge was reduced to misdemeanor trespassing. Even if it failed to deter others (which I don't concede), putting these people in jail would stop these same people from committing the same crime again, which at least would be an improvement over the current situation.