At the Academy, they said, "There is a gun at every call; YOURS!" The public doesn't get that. A temporarily blinding punch in the nose or strike to the head and an unarmed perpetrator going for your gun and you have a fight for your life. Law enforcement officers take an oath, but they aren't getting paid to get hurt or killed. It's not "all part of the job" any more than dying in a fiery crash is part of having a driver's license.
I once arrested a man who had what looked like a toy gun in his pocket. It was painted sky blue and had white plastic grips. It was a loaded 22LR revolver. Getting shot at numerous times didn't scare me as much as finding that gun because I knew the great majority of officers would hesitate to react. An officer I went through the academy with shot and killed a homeless man who committed suicide by cop via pointing a toy gun at him. It traumatized my friend. Incidents like these create a huge divide between law enforcement and the uncomprehending protected public.
Play stupid games, win stupid prizes.
It's called reasonable threat
...And in another part on town cops fatally shoot a black man who was holding what was believed to be a broom over his shoulder but was actually an RPG.