Now that the dust has settled a little bit, I feel like I need to put my two cents in on this whole thing.
There seem to be a lot of people posting from the outside looking in. The gun culture in Colorado Springs isn't completely unhealthy and the number of responsible firearms owners very greatly outweighs the number of deviant owners. Open carry is a thing here and it isn't like the pictures where folks carry around rifles. You see people with holsters and handguns, very discreet unless you're looking for it.
Members of my family have been involved in pistol instruction here in town and they get such a varied amount of people taking classes. You'll have a retired schoolteacher who wants to know safety for her home. You'll have a banker who wants to know how to properly operate a pistol so he can go to the range with his buddies. "Gun culture" as it's been appropriated by the internet is in full effect here.
We have several well known shooting ranges in town and you'll see fairly high attendance on almost any given day. You'll see a decent number of AR-15s, too. They aren't automatic, and they aren't nearly as menacing as some other firearms you can legally purchase. Above all, safety is what is taught and practiced at all of the ranges in town and the operators of such facilities are very strict about it.
Now, I personally don't own a firearm, but my roommate does. We live blocks away from where this shooting took place and it's very unnerving. Downtown Colorado Springs does have a homeless problem, but that isn't the issue. Legal weed and the military aren't the issue either. In this case, it was one maniac who happen to have access to a rifle.
The amount of gun violence in town is very low compared to other cities with similar populations, despite there being more firearms owners per capita. If a gun wasn't available to this person, the violence would have still occurred, I'm sure. The gun isn't the issue here, and people need to look at who is pulling the trigger instead of blaming the weapon.