The map in the OP looks "off" btw. Do note that it's from the Huffington Post.
This is why you have to be offensive in your defense. 1 man defending his family in the city is nothing more than a target for roaming hoards of pillaging thugs.
Bump that up to 3 males and some capable females and you have a chance. You can not hide in the house unless totally gray. No light....no signs of food or what they will be looking for.
Put up a strong defensive front and those without tactical training and sufficient ammo and fire power will move on to softer targets.
Great. This means that in order to survive I'm going to have to team up with the drug dealer across the street. I know he's armed, so with him, me and my wife that makes at least 3 who can shoot. The rest of my neighborhood is a bunch of soccer mommies who would at least be the ones that the pillaging thugs go after first.
This ^^^That's mostly an artifact of how they are displaying the data. Looking at the map you'd guess most of Michigan was just as dangerous as Chicago, but that just ain't so.