P.S.: Oh, and it is not the people that "love" guns the more inclined to use them as a tool for a crime. Maybe on the contrary.
I've known some gun lovers in my day. Some of them, you could even call them "gun nuts". They own several, many, and go to the shooting range quite a bit. And I can tell you than a true gun lover will make it known to you within the first 20-30 minutes of conversation with them, they are that passionate. Everyone in their circle of family and friends, and often even at their workplace knows that they love guns.
So they want us to believe that someone that supposedly owned 30+ guns never once mentioned it to anyone? No family even? Really? And this guy never practiced shooting with them anywhere? Again, really?
Well, those are really "gun nuts" as you say. I like guns, but wouldn't consider myself a "lover" at all. I own several but rarely go to the shooting range. Most of the time I just don't even remember I have them until I have to renew the licenses. Only a few people knows I have them -not that I have any reason to HIDE it either-.
But most of all I learned (or was "teached") to respect them since I was a child.
I would say it is more probable that someone that hasn't learned to respect guns through his entire life and just have the economical means to buy a BUNCH of ILEGAL firearms (I think owning full auto is illegal in USA) would have more probabilities to become a mass shooter. More so if he just recently bought them for this. No need to love guns or anything.
And don't tell me a multi-millionaire guy would have much difficulty in buying that arsenal of ilegal guns in the black market.
Also, you don't need to practice much for shooting into a 1km square full of people (20.000+) from 300m distance with a full auto. Just the basics of the gun functions, reloading (which btw took him a very long time), etc.... No need to really aim beyond an instinct orientation into the mass of people.