I don't know who [deleted] is, but he sure makes a lot of comments.
And he(?) is correct. We all have the right to choose where we spend our money. But just as Costco can't tell you to wear a mask in your home, you can't tell them that you don't have to wear in their store. And honestly, this opposition to wearing masks is just the epitomy of childishness. Wearing a mask, whether you believe it works or not, does no harm to you. Stop being an asshole.
MiniApplels is right, too. Whether by Costco or anyone, no one will miss this guy.