He's stating there is no correlation between gun violence and gun control. And just because there is an inverse correlation in this instance, that still doesn't mean that there is causation.

>I'm getting the impression that large American cities are basically like the Thunderdome.
Mostly just Los Angeles and New York, but NYC became habitable after the mid 90's and LA stopped being an issue in the early 2000's.
If you should be worried about anything in those cities it should be the weather and traffic, which is what we all were doing anyway in our respective cities.