Hoarding ammo? Generally speaking, the hoarders aren't those folks who keep their normal supplies of ammo. While some folks keep more than others, those with a goodly amount on hand probably had plenty.
The hoarders in this case seem to be those people (not a mutually exclusive group from the former, you understand) who are buying out of fear they won't get a chance to buy again and are buying more than they would normally ever buy, often times many times what they would normally buy. Moreover, people who have gotten into hoarding that previously were something of ammo snobs, showing amazing disdain for ammo such as Wolf, Blazer, etc., not miraculously have found a very good reason to buy up ammo that previously they would never consider shooting in their guns, let alone actually buying some of it.
For me, the difference would go from buying maybe 5 or 6K of ammo per year to buying 20, 30 or 40K rounds of ammo per year when my consumption hasn't changed. Then I would be in the hoarding category, IMHO.
What gets me, and maybe this is smart, maybe just part of the panic, are the people who buy ammo in calibers they don't even own. If they can't find the ammo they need, they buy up what is there, ostensibly for the purposes such as trade for what they do need or for reselling it. A buddy of mine now has a couple thousand rounds of revolver ammo, purchased a box at a time, who gives the excuse that he might buy a revolver in that caliber some day. He didn't start buying it until after the panic started and so is paying some inflated prices for ammo. So who in their right mind decides buying up inflated price ammo for a gun they don't own with the excuse that they might buy such a gun someday...if they aren't hoarding?