It's already been said "If you disagree with the policy, don't go there"
I completely agree with everyone's anger over these sorts of policies, but maybe he (the owner) had an experience that prompted him to put up the sign. Unfortunately, all it takes is 1 bad apple to give all gun owners a bad rap.
Last year, at The Olive Garden, in carson city a guy pulled out his carry weapon and proceeded to muzzle sweep many people and, brandishing the weapon, threatened the waitress/cooks because he was unhappy with the food/service. That's all it took, 1 (insert expletive here) to ruin it for everyone, now Olive Garden has a polite sign on the door banning patrons from carrying guns (meaningless in terms of state law, though). Plus, think about how ugly the situation could have gotten if another patron had a gun (since the perp was threatening people and waving a loaded gun) had he been shot, then the resteraunt has expensive haz mat cleanup fees, negative media attention, etc.
BTW, he was sentenced last month, got 3 or 6 months, I don't remember.
Again, I agree that these signs are wrong, but I can also understand where the owners are coming from.