That pretty much prohibits any kind of law enforcement that utilizes potentially lethal force.
If you've ever worked in public safety or law enforcement, you'd realize how uninformed that opinion is.
Law enforcement officers don't carry weapons to use them, they carry them as deterrent. Good law enforcement officers regard the use of deadly force as either a last resort measure or just bad police work.
In real life, there is no escape from balancing potential risks (in this case, of innocents being killed) and benefits.