I know this reply is from a long time ago but I just have to point out the stupid.
it doesn't matter if they could have, they don't have to, its the law and they where only following itDon't use a mental illness
Do you really not realize that as a police officer you are obliged to take non lethal actions first in order to cause as little loss of life as possible? Non lethal rubber pellet shotguns will seriously forget you up, there was nothing the homeless guy could possibly do anyways after he had been flashbanged, and getting shot with a non lethal rubber pellet shotgun would've dealt with him very quickly.
In addition to that, they flashbanged him when he was picking up his belongings after he said he would go with them, and they decided to be aggressive as forget and not give him the time he deserved to pick up his stuff so he couldn't be charged for littering or some stuff.
How loving stupid are you?
If a guy pulled a knife/gun/other weapon on me, I'd aim for the head first thing.
You're being extremely naive. For one, you're not even supposed to aim for the head, its all about center of mass. And secondly, if you were actually in that situation there's no loving way you could do it without hesitating. The knowledge that you ended a life instead of trying to find a much safer, less traumatizing way to handle the situation would probably wreck you. Thats why soldiers don't like to talk about how many people they killed, even though it was pretty much always self defense kill or be killed for them, it just takes its toll on their mind and it gets hard to live with.