As to why the general US public require assualt weapons in urban environments, or even for farming, is beyond me. In Australia, assault weapons & semi-automatics are banned. If you want to go hunting (Kangaroo, Deer, Goat, Water Buffallo or even Crocodiles) then you have access to bolt action rifles which means you need to be a well trained shot not some hill billy that sprays and prays.
So I come back to the US issue being one of culture, the desire to have fully automatic assault weapons and destabalising psychotropic drugs being over prescribed resulting in people whom loose the plot and have access to military grade weapons.
The exceptions to this would be what we consider dangerous animals, like wild pigs. These come at you and come after you, and you had better have some serious firepower. Large caliber pistol, eg, Dirty Harry's gun, comes to mind. And this is essentially a self defense problem, not hunting per se.
Very few people in the US desire "fully automatic assault weapons". Semi automatic, such as the Glock in handhelds, and modern rifles, are likely what you meant to say. There are to my knowledge no cases of "fully automatic" weapons being used in crime in the USA, unless you literally go back to the 1920-1930s prohibition era, "Machine Gun Kelly", etc.