schv-
Sorry, it's not that simple. If the guy was unstable, refusing to drop the knife, and within reach of other churchgoers, the officers could very easily conclude that he was too much of a risk to the other citizens there. What would your response be if the officers had tried reasoning with him some more, only to have him lunge and and injure/kill a bystander? "The cops should have acted sooner!"
Here's the problem- handguns don't reliably put people down, especially mentals or folks on drugs. Had he gone for the officers or a bystander, even if they had been able to react in time to shoot him first, there is no guarantee their rounds would stop him before he could kill someone else.
Now, if he was in an area where they could cover him and safely evacuate the congregation, they should have (and probably would have), and then locked down the church and brought in the professional negotiators. The article doesn't give us anywhere near enough information to determine what the exact circumstances were. I can pretty much guarantee you that the Attorney General's investigation covered those bases.
It's an unfortunate fact that the general public has no idea how dangerous EDP's can be, or how dangerous edged weapons really are. A normal, sane person can close a gap of 21 feet in less than 2 seconds and kill you with a knife before you can draw and fire a handgun. A normal person can conceivably function for 30 seconds or more after being shot in the heart with a handgun. If your wife and daughter were in that church, how much leeway do you want the cops to give the knife-weilding EDP, given those facts?
Your statement is simplistic and based in ignorance.