<sigh> read the letter, read the letter, read the letter. He won't do business with the RG because they do business with stores that sell guns.

What you're proposing is not punishment: it's a further dividing of the populace along political fault lines. You can bet your tofu turkey that the Cabela crowd will henceforth boycott stores that do NOT sell guns. This is what the Divider-in-Chief hopes for.

An aside: I cannot wrap my head around your contention that "It is not a normal business practice for a store to sell guns." when you list 8 mainstream chain stores - including just about every hardware store in the US - that sell guns. I would agree that it would be strange for a yogurt shop or hair salon to sell guns.. but a sporting goods store? You should get out more.