Absolutely not. That and the "rooftop sniper" idea are how you get Bloody Sunday. Firing into crowds is indiscriminate mass murder. As is detonating bomb drones in the crowd.

What if LEO don't have LoS? What if that violent person is in the middle of a massive crowd? Article says this drone can fly at 90 mph, which means it can get to the threat muuuuch faster. For a gun, you also need personnel on the ground, which puts them at risk and they can cover only so much area. A drone at a good enough altitude with a streaming camera can send it back home for constant, automagical scanning and threat-profiling.

without harming the others.

Humans aren't good in stressful situations and their aim isn't great. A ground view isn't necessarily helpful in situation where the criminal might be inside the group ring.

And then all the other people pull out guns and think that you're the shooter. Or maybe you miss and kill someone else.