Put an Ironman suit on a cop and he isn't going to much care if the potential perp is carrying a knife.
It's a weird gig (street patrol) and it's hard to have a strong opinion on it without actually being a cop or going out on numerous ride-alongs. Naturally, it's easy to come up with 'solutions' behind the safety of a screen.
One thing that brought that home to me is having several friends who are retired COs (Correctional Officers) from the California state system and several friends who are released felons. One thing their stories taught me is that people who are uninvolved in those systems don't know a thing about it and have nearly useless theories on the way things-oughta-be.