Well cops need guns in the states because the whole shoot a guy in the knee with a rubber bullet routine doesn't work in countries where the risk is so high. People bring up Australia, but the population and the culture are so different. In Australia you've got the white people, the Aboriginal community and a few Asians here or there. They don't have a ghetto. And I'd be willing to bet money on an Iraq veteran or whatever going solo on the cops trying to disarm him. This also doesn't stop guns from coming from Mexico, either.
The messages the Left has about guns is sometimes admirable, being so against violence, but the execution, the way they want to do it is like a boat with holes in it. Yes, stopping gun violence is important. But the how is also important. Not every good idea works when applied to a different situation. This is much like the Sanders crowd talking about free college. Nothing is free. Do they know how it's free? Where's the money coming from? What happens if the job field becomes very crowded and many degrees are rendered useless? (Not like that hasn't happened already. . .)
I'd like to explore other methods of stopping mass shooters with more focus on mental health in the country. That to me is a risk free investment that helps prevent lunatics going looney in the first place.