I wonder if that's because the US military felt it had/has its back to the wall in terms of the success of its mission, and thus was forced to do the more effective thing, even though it's a bit outside of the purpose of their organization.
Conversely, police departments aren't under that much pressure to perform. Our country is experiencing a peace wave.
Instead, they're free to worry only about protecting their turf and increasing their budgets, through wasteful vanity projects like their tremendously overused SWAT teams, and over-targeting non-violent drug users.