That's based on the premise that adding guns to a situation improves the situation.
It is based on the premise that adding your own gun improves your odds of defending yourself against someone who is shooting at you.
I would suggest that a police officer is more likely to defuse a situation rather than escalate it if he doesn't have the means to escalate it.
If someone is shooting at you then you either fight back, run away or hide. Those are your options. I am not sure that I want my police force to run away and hide when confronted with a violent person nor is it fair to expect them to confront gunfire with anything less effective.
The police need the authority and ability to contain any violent situation that they may encounter and the problems only arise at the level of the individual when they abuse or exceed their authority. So more screening, more training and more accountability. Requiring a degree in anything would be a good start.