More Guns In Chicago

One of my favorite bits of fiction peddled by the Gun Cult is that Chicago, a city that heavily restricts guns, is a great example of what gun control really does...create more violence and leave ordinary citizens defenseless.  So, by this logic, if Chicago were to loosen its gun laws and allow more people to have guns, violence would decrease, correct?

I'm curious...what is the basis for this line of thought? And how would a fully armed Chicago look if the laws were indeed changed?