So Dick's bought the gun maker's guns and then destroyed them. That's great for the gun maker, since they can effectively sell more guns now. The number of end users (buyers who purchase something and do NOT resell) actually went up. Before this, Dick's was a middle man. Now Dick's became an end user (which uses the guns by destroying them). It might have worked 1,000 years ago when there was no internet or phone and people didn't travel much, but buying from a different middleman is no big deal these days. Funny but Dick's would have done more damage to the gun industry by giving these away for free since it would have a small effect of reducing the value of these guns.
Way to go, clown!
You don't seem to understand what's going on here.
Any retail chain is well aware that their customers have multiple sources for their goods. That's what the word "competitor" means. To imagine this particular retailer is under some illusion that destroying their stock somehow means no one will ever buy that item again is profoundly naïve.
All Dick's is doing here is clearing its own conscience, dumping what it considers dangerous goods where they can never hurt anybody, which means there's zero chance that they will bear any responsibility out of having ordered them in the first place.
It's the same as if Dick's Drug Store was selling cigarettes and when it dawned on them what the effect that product has on people, so they pull all the tobacco off the shelf and toss the stock into a bonfire --- since their purchase from the tobacco companies was done in good faith, they can't ask those suppliers to take the stock back for a refund. They'll take a hit on what they spent for that stock, but obviously they consider the principle more important than money.
And that's how you get it right.