Starbucks is tired of being ground zero on the gun debate and
wishes gun owners to stop carrying in their stores. And to drive home the point that we are our own worst enemies,
gun owners decide to be dicks about it.
UPDATE:
EDIT TO ADD: The whole point behind the open carry movement is to let the citizenry see us out and about amongst them doing normal people things,
JUST LIKE THEM, except with a sidearm. Our goal is to make them comfortable with us carrying, or at least not terrified of us just because ZOMG!!! GUN!!! We never expected to convince the antis, our goal was to convince the fence sitters. How do you think we did in this instance?
END EDIT
I'm sure that the carry of pistols wasn't such a big deal, but the first jackass that brought a rifle in started the decline. Seriously people, just because you can do something doesn't mean that you should, and rather than just thank them for their position we chose to make them a battleground.
And now Starbucks will likely adopt the policy that the anti-gunners wanted them to adopt all along and post their stores, therefore making it illegal to carry in their stores, and it will be our fault. We have effectively moved Starbucks from the "neutral" column towards the "enemies" column.
Well done.