...But they absolutely have a right to defend themselves , up to and including using lethal force when necessary. I make no judgements whether it was necessary in THIS case because none of us know the facts yet, but in general terms some have this idea that the police should never shoot anyone and that is just stupid.
Of course they do, just like you and I. OTOH, I don't have a right to shoot you once, much less four times, just because I
think you
might have a gun. Being a police officer doesn't give them psychic powers nor allow them to shoot anyone they please. They must follow their department's policies on the use of deadly force.
Self-Defense Overview - FindLaw
Self-defense is defined as the right to prevent suffering force or violence through the use of a sufficient level of counteracting force or violence.