Personally, I don't like to criticize other people's business decisions unless they genuinely don't make sense for the good of their business. If walmart, dicks, and CTD want to stop selling certain products, that is their prerogative. They likely did it because they thought it would protect their bottom line, and that is their main interest, not preserving our liberty. Walmart also used to sell handguns, and because of pressure from anti gun groups stopped. I have no real problem with that. If the anti gunners want to convince people to voluntarily stop selling weapons, they have every right, and retailers have every right to choose to do so. It is when the government, or anyone else, uses force or coercion to make retailers stop selling that it becomes immoral.
That said, I'm sure they would be sold out anyway, and from what I've heard, they still have them at walmart, just not displayed. Now all it would take is for some news team to go into a walmart, and show how "these evil baby murdering assault weapons are sold over the counter at walmart" in a ploy to play up the "proliferation of these weapons of mass destruction", and it's bad press for walmart, next thing you know, they permanently stop selling semi auto rifles, like they did with handguns.
I think the NRA, and retailers, did the smart thing by laying low the first few days after the shooting, there would have been no reasonable dialog, only pure emotionally driven insanity. We all saw the calls for the murder of NRA members even from elected officials.
Of course that now gives us ammo to use against them. "I need this rifle to protect me from people like you! You called for the mass murder of me and people like me! I'd say that's a pretty good reason to not give up my gun, or the ability to purchase more in the future." Even less genocidal responses from celebrities and elected officials were extreme to say the least, most calling for total gun confiscation and other tyrannical measures. We can now point to them and say, "See, they really do want to take ALL the guns, not just my black rifle."
