The article you linked says that it's "unrealistic TV shows" (their words, not mine) that convinces people to do stupid things like shove guns down their pants. I think it's pretty obvious that this guy learned everything he knows about guns on TV. If he'd ever had even a basic course on gun safety, he would've known not to do that - or at least, not to do it with a round in the chamber and the safety off.

It's analogous to a kid thinking he can drive a car just because he's watched his parents drive.