While you're right in that the person doing the shooting is far more important than the weapon, it's pretty clear that some weapons, like fully-automatic shotguns, are designed for specific use cases. You wouldn't use a .50 Barret to hunt deer, and you wouldn't take a micro Uzi to the practical range.

Drawing a line between civilian and military use suitability is difficult, but that doesn't mean there is no difference. That's why there is no assault rifle law in the US, but rather some features of weapons have been banned from private use.