No they are not. They are trained to shoot to stop the threat. I was on a paramilitary force protecting a vital area (imagine Ft.Knox, but higher security), and we had a lot of former cops, current reserve/auxiliary, and ex-military about to go to the academy looking for a resume booster.

We all get the same training (which is the same as most civilian CCW courses): We are trained to shoot to stop the threat, and to continue shooting until the threat is no longer present.

Police are trained to shoot "center of mass". Top link in that search query is about this very issue we are discussing. (before anyone asks, I cut the cord on Google and avoid their products and services for anonymity/privacy reasons. That's why I use duckduckgo)

Center of mass is typically the center of the chest, but if an adversary is behind cover/concealment and is peeking out, it can be the center of the head, or the center of an exposed portion of the arm.

Center of mass is a useful concept because it allows for inaccuracy in shooting while still netting the most combat effectiveness. If you aim for a leg and your shot is off by 3" because you just sprinted and your adrenaline is pumping, you're going to miss the leg and who the hell knows where the bullet will end up. If you aim for the center of the chest and you're off 3", congrats. You still hit the adversary in the lung, or maybe took out a good chunk of the spinal column.

There are two exceptions to center of mass shooting: pelvis shots, and body armor.

Pelvis shots are highly controversial in the world of defensive shooting. Some schools of though (like Massad Ayoob) claim that shooting out the pelvis is a good way to stop a slow-moving adversary armed with something like a knife or a bat. If you shatter the pelvis, the ability for the adversary to locomote is defeated. My opinion is that if it warrants shooting at all, the situation is warranting a shot to center of mass. You will be in a reasonable, imminent threat of death if you don't shoot. If you aren't in a reasonable and imminent threat of death or grave injury, there is no justification (legally or ethically) for shooting.

The other quip is about body armor. Two to the chest, assess, then a followup shot to the head. This is fairly self-explanatory. Most body armor can defeat the common pistol calibers, so if two good center of mass chest shots do not incapacitate the adversary, you followup to the head.

The intent is never to shoot to kill, it's to shoot to stop. Sometimes shooting to stop ends up in a death. Sometimes a head shot is the only available shot. But defensive shooting is all about stopping threats, never killing.