If I walk into a gun shop, I expect to see weapons, and people, and people carrying weapons. People in a gun shop may well be buying weapons. I do not shoot them. I do not panic. I do not call 9-1-1.
If I walk into an airport, I expect to see luggage, and people, and people carrying luggage. People in an airport may well be buying magazines, but there are strict limits on how many rounds of ammunition these contain.
Wal-Mart is among the highest volume sellers of firearms and ammunition. Yes, Wal-Mart is a gun shop. They are in the business of selling weapons (also toys and toiletries and tires). Accordingly, I expect to see weapons, and people, and even people carrying weapons.
It might be somewhat surprising therefore, that an armed man strolling through Sky Harbor airport is met by arrest, while a cellphone wielding man strolling thru Wal-mart with Wal-Mart merchandise is met by a hail of bullets.
Might be, I say, knowing, as you do too, that it is not surprising in the least that a black man is dead, and a white man is alive. Welcome to post-racial Amerikkka.