Normally I would never say "good" when a place stops selling guns, but f*** these people. I hope they stop selling guns and ammo entirely, at least other gun shops will benefit from the business and it will keep gun owners out of their stores and in other stores that suck less.
This could actually be a net negative in the long term. Especially in places like New England, where gun owners are definite minority- the reality is that most young people will have no actual exposure to seeing a gun store. Their impression of gun stores is informed almost exclusively by media portrayals which are, too often based on negative stereotypes. Dick's is one of the few places left that is not a gun store (or a hunting or outdoors specialty store) which still sells guns. When parents take their kid to get a CO2 fill for paintball, they go to the gun counter. Same with people buying some other products that happen to be there for various reasons (like loss prevention). There are also times when kids will just see that area, regardless of what their parents might want (like when they go shopping for apparel, sportsball gear, etc....). By having guns and ammo there, it made them more normalized- which countered the taboo that current social trends are imposing.
In coming years, one of the things that we are going to need in order to counter the progressive paradigm is a sense of normalcy.