This is what happens when you give weapons to people: you get both policemen and and civilians being shoot. These coops killing unarmed people are asking to get shoot by pissed off friends/families of the victims.
When you don't allow citizens to buy guns, criminals still get guns and police still have guns. You just withdraw the freedom to have guns to honest citizens.
The governement allows people to drive which is far more dangerous than allowing people to have guns.