Well, unlike you I don't know every single law in every jurisdiction of this country, but generally LEOs can only use deadly force when their lives or the life of another are in jeopardy. This is the same for non LEO's. If you shoot somebody and you can articulate that you had no other alternaive, then most likey you are going to be exonerated. Which happends most of the time in this country.
For every cop who went to jail for a shooting, 10,000,000,000,000 have shot unarmed citizens because said citizen, “made a threatenting move in the direction of his pants.”
Do you have source?
happends=happens
Unlike you, I read posts here on FR where innocent shooters are prosecuted all the time. Do you have a source for your claims?