The article says "showing the weapon to a teenage visitor". Not showing him how to use it. Regardless, apparently the kid was handed a loaded weapon inside a home when he either had absolutely no idea how to use it or very certainly did. One of the problems with everyone insisting on exercising their constitutional rights is that not everyone is qualified to do so wisely.
This is exactly the problem, when it comes to Americans you just don't know who actually knows about gun safety since it's in no way required. At least I find in Canada I can be relatively comfortable around gun owners since although we have idiots we don't give every idiot a gun because freedom. This guy couldn't have cared much about gun safety if he handed a gun to a teenager without making sure he wasn't going to shoot. My ex would hand me a gun he knew was empty and still expect me to check myself and also never ever ever EVER point it at someone.