They also get kicked in by gun wielding cops and not uncommon for them to shoot the confused armed house-owner who thinks they are criminals - even if the house is the wrong one.Guns are now aligned with conservative ideology in the United States. One is a proxy for the other. So yes, it's definitely "because I can" somewhat (the general I here). It's a political fashion statement, I'd say, or at least the AR-15 craze is.
I'm from the South, so long before this started, it was extremely normal for people to own firearms. Rifles and shotguns for hunting, sidearms for collecting/personal defense (or hunting). Personal protection too, of course. We have a lot of brazen crime in the states. Peoples' doors get kicked in by gun wielding criminals, so there is definitely a "if all the criminals have guns, I want a gun too" thing. I don't find that particularly irrational, although I do fully recognize that the need for defensive use is relatively unlikely.
Anyway not looking like any gun legislation is in store anytime soon, Republicans are going to try and slow walk until the news cycle moves on ...until the next one.