I have a nephew who came into the world somewhat obsessed with weapons. Medieval weapons, mostly. It is so unlike his parents, both artists, or his older brother. It was just there. THey fought it for a while, when he was a preschooler, but then when that didn't help, they fostered it in a healthy manner. Now he is in high school, and not even slightly violent (never has been), but has been taking blacksmith courses and making his own knives and other various blades -- and they are absolute works of art. He is an expert on the subject, and I've learned all about Damascus blades and the like ... it's really interesting. And just not scary. Obviously this AR kid is a bit scary, but a knife collection on its own doesn't mean squat.