I don't think you can safely infer that absolute ("only") from the parent comment. Nevertheless...

1. Police are often a large percentage of a city budget, so if all city expenditures were decreased equally, it would inevitably look like the police were giving up more in absolute terms.

2. If the current solution to the problem is only more policing, then the only thing in the "solution to this problem" sub-budget that could be reduced is the police. In other words if X is the amount allocated to the problem and X is currently 100% police, it may be worth rebalancing X to a more diversified portfolio.