Well, here's the thing. He's not wrong.
Great thing about an AR is they don't kick worth a squat, they shoot really flat and if you miss the first time, you just go plinkplinkplinkplinkplink until the prairie dog is either underground or pink foam.
In a simpler world you did this with a .22, probably even a bolt action one. But because the powder charge is a fraction of 5.56, the slug is going like half the speed despite being roughly the same caliber. And since nobody of conscience sports .22LR for "self defense" the proliferation of 5.56 has made it so you might as well take out a coyote with the same caliber you used to take out the 'cong with.