I'd dispute his underlying assumption. The safest states for violent crime have the largest number of firearms per household. The unsafest states (and the District of Columbia) have the fewest firearms per household. The typical response, of course, is to conflate homicides with suicides. The problem with doing that is individuals who choose to suicide would naturally use an easily available method.
In Western states that would be a firearm. In New York City that would include jumping from high places, jumping in front of a subway train and drug overdoses. And the problem with that is that absent a suicide note, a medical examiner has no possible way to know if a fatal fall or a subway death or a drug overdose was a suicide or an accident. Absent information to the contrary, it will be assumed to be an accident.
There’s an easy way to get to that umber that makes it totally unreliable. Most individuals who are in the violent crime business, like drug dealers, probably do illegally own and use one or more guns, like the Chicago gang bangers. In the course of their “business” many are going to be shot and killed, but not with the guns they keep. Nevertheles, they go into the number of people who were killed who had guns in their homes.