> you need little to nothing to convince you that deadly force is fine.

I'm disturbed by that line of thought. A normally educated human being from a developed country should feel bad about using deadly force, and worse after using it. The whole point of military training is to break the human instinct no to kill and even with the pressure of actual combat situation (where the upside is much higher, the downside much lower than for SWAT teams), killing breaks the soldier mentally.

What kind of people is the US is selecting (or what kind of training) for its police force that only some fear of criminal prosecution is keeping them from shooting people ?

After shooting dead an innocent, you would expect a police officer to be mentally wrecked. Even worse as he utterly failed at his primary mission of protecting the citizen which, as a Police officer, should normally be pretty high up in his list of personal priorities. So I can of understand going easy of the Police, from a legal point of view. But if the kind of people you have in the police are the one looking for the license to kill to assuage their most primal instinct, the problem is not with the legal side, you are hiring/training really wrong. That's not a police force, that's a criminal cartel.

Im sure there is grief afterwards, but there is also grief and pain from over eating and overdrinking: some consequences are very hard to measure at the point of decision. Specially when its related to your own survival.

The ghost of a 1% danger vs a 0% consequence makes it a pretty rational decision. Bear in mind that criminals, even those with hostages, dont make the decision to shoot so fast: they know that if you shoot the hostage you die or get captured immediately. So the criminals do respond to the punishment. Why wouldnt cops?

US is hiring lots of former soldiers as LEO. Also the training for the soldiers is not to break the human instinct not to kill (there is nothing like that), but to follow orders, react quickly under pressure, reduce the risk of panicking and to use superior tactics for killing the enemies. We train soldiers to be effective killing machines, nothing else. And many become LEO after retiring from the army.

You're right, US police officers are trained to be less hesitant in using force than would be natural. They are taught that at any moment they could be in a life and death struggle and that they have to have a "warrior mindset" to react quickly before it is too late.

"Better tried by twelve than carried by six"

It really does seem that simple. Most people will behave similarly in similar situations and American cops have so many perverse incentives.