My gut reaction is Big Fucking Deal.
Walmart has never been my go to place for gun or ammo shopping. Toilet paper, good generic OTC drugs, food, hell yeah.
But even ammo, never mind guns. They are a total pain in the ass. Tiny hidden kiosk with everything locked down and not a clerk in sight. Contrast that with Academy, people behind the counter and a real stock of a variety of firearms.
When people were bent out of shape with Dicks, I pointed out that their golf stock was bigger than their knives, guns, ammo and fishing gear combined. Some things you go to Cabelas or Bass Pro for. Neither of them are much on golf or tennis.
As for open carry.
They have as much right to post no open carry or for that matter no carry as any other business. As far as I’m concerned the Tommy Tacti-cool/Mall Ninja open carriers are just making it harder for folks who show a little discretion. You aren’t in the middle of a war zone. You live in the USA, a relatively safe place to live.
If you don’t believe me check out the crime stats. The same ones we love so much when they help us defend the Second Amendment.
Mostly though. Don’t be an asshole posting threatening crap on social media. It doesn’t help the cause and make you a target.