Earlier quoted context omitted.
Assault rifles are automatic. We haven't been seeing automatic weapons in mass shootings. You might mean "assault weapon," but that's a poorly-defined political term that can include cosmetic attachments and colors. And plenty of people get AR-15s for home defense.
You are missing OP's point. A shotgun is a far better home defense weapon than an AR-15. So is a handgun. The AR-15 was very carefully designed for intermediate range combat.
It's also irrelevant. Home protection isn't the only reason you'd have a gun in a rural setting. They're also quite excellent for keeping groundhogs and coyotes off of one's property, and for recreational purposes.
This mindset of people who know nothing about guns (e.g. not knowing what an assault rifle is) claiming "You should only be allowed to have what I think you need" is the exact problem at the heart of this discussion.