Not so weird... A Knife I can understand. There are a number of uses for a knife beyond being an offensive or defensive weapon. I'm not a knife person, personally, but even I have a few to cut food, or open sealed boxes. I've seen knives used to cut bindings and they can even be used to craft art (whittling being an art form where the knife is the primary tool of choice)!

A gun? Outside of a legit, active warzone? A gun either says you're hunting, or your scared. That's it! I have all the respect for a hunter going into the forests to hunt game animals. I do love myself a burger and a steak... but in a public setting? What're you hunting? What utility is a gun in a public Walmart?