And the Constitution gave you the right to own a tank or even an atomic bomb.

That scenario is not so much about "need" as much as it is a matter of want. Over the years I've known a number of hunters, some of which prefer using an AR-15, and not one time did any of them ever indicate that they "needed" that particular style of rifle.

No two styles of firearms handle exactly the same way, and in some areas an AR-15 may have a few more pros on its side than cons compared to bolt and lever action rifles. An AR is more compact and manuverable, highly modifiable, and consistently accurate. Perhaps maybe one down side there would be range, they aren't really suited for extreme distances. Still, the pros outnumber the potential cons when using that style of rifle for hunting, especially if up against a group of animals like say, coyotes. So it's not really about needing as much as wanting, and if the hunter in question likes a highly modifiable weapon.