Every time someone brings up the "highest prevalence of violent crime/lowest prevalence of gun ownership" relationship, I feel like I need to have a conversation about statistics with them. A very rudimentary understanding of "correlation does not imply causation" makes even the biggest gun ownership proponents question that argument. There are a million confounding variables that likely better explain why metro centers have higher rates of violent crime per capita than their suburban or rural counterparts. It's fear mongering at its very core.
I'm a proud gun owner, too. That's just such a poor argument for why someone should own a gun.