Saving some for the next guy...
I saw this play out at a Scheel's in Fargo, ND about 3 weeks ago. Scheel's got a boatload of Remington 115 grain 9mm and filled all their previously empty handgun ammo shelves with the shipment. It was a little awe inspiring. There was NO other handgun ammo on the shelves, just box after box of 250 round 9mm for about $87 a box (that works out to be about $14/box of 50 says Dale, darn near a math protege).
Several guys, myself included looked at all that ammo and said, "Eh. I guess I don't really need any more 9mm." Which I don't. So I walked away mentally adding $87 to my "next gun fund" account.
Did I feel virtuous? Yes, a little bit.
Is that a stupid feeling? Yes, a little bit.
Another story is back during the great .22LR drought, at my local Fleet Farm I found about 7 or 8 bulk boxes (I think about 550 rounds) of .22LR on the shelf for a reasonable price. I dithered over getting some and finally threw one box into my cart. A gentleman waiting patiently behind me moved up and swept the shelf clear of the remaining boxes.
Was he "wrong" to do this? IMhO, no.
Was I "correct" to take just ONE box? Eh. I didn't really NEED even one box so maybe I shouldn't have taken even one.
Is this anybody's business? IMhO, no. There's LOTS more stuff to get your moral outrage on than setting yourself up to judge what other people buy, or eat, or drive, or...you get my drift.
P.S. I totally understand and support gun shops that keep back ammunition to sell to a customer that buys a gun from them. I sympathize with a brand new gun owners with the shiney new firearm in front of them being told there's no ammo for them and they won't be able to try out their gun at all.