Before I start, I'd like to say that I agree with pretty much everything MrCoolDale wrote above. Well said.
I've been trying to condense my thoughts ... but I couldn't. So here it goes anyway ...
I think that the gun community must learn that there is a difference between "open carry" and "political open carry activism," and that a business that proclaims neutrality on a political issue does not want political activism re: that issue in its stores.
If all of those who were open carrying had simply been going about our normal daily business and carrying a firearm, we might have had a different outcome. In an ideal world, open carry is boring. You perform your normal daily activities like anyone else. The only difference is that you have a pistol strapped to your hip for the purposes of self defense and/or criminal deterrence.
If we're going to normalize open carry, we need to "be normal" when we do it (which is how most of us in DE do it, AFAIK). Can we choose to patronize or not patronize a business based on their firearms stance? Sure. Can we let them know about that part of our decision? Sure. But that's basically the same as patronizing or not patronizing a business because of its organic farming (or lack thereof) practices and telling them about it. It's simply choosing to make a business' stance on firearms one of the factors in whether or not that business receives our $$.
IMO, a big part of the problem occurred in states where open carry of a handgun is illegal but carrying an unloaded long gun is legal (notably Texas). Given the options, some of them decided to carry unloaded long guns - which is, IMO, not really open carry but instead is political activism. An unloaded long gun isn't a weapon unless it's used as a club. A video recording transforms it into a political stunt.
Is there a place for political open carry activism? Of course. Normally it's in front of the legislative building when they are attempting to pass an idiotic bill into law, or online / on the phone to politely inform your legislator/political executive that they should/should not pass a certain bill. It's not at a business that has proclaimed neutrality and allows everyone to exercise their Constitutionally-secured RKBA.
Imagine if a business took a neutral stance (no stance) on abortion. One side decided this was unacceptable, and so they wore shirts with pictures & slogans about how rape victims need to be able to choose. The other side also thought it was unacceptable, and wore shirts with pictures of aborted fetuses. Both sides videotaped their actions and put 'em up online. It wouldn't be surprising if the business simply said "no political activism in this store re: abortion - take it elsewhere."
That's what Starbucks should have done, IMO. They should have said "no more demonstrations, pro or anti gun, at our stores." But unfortunately, they decided to essentially endorse the anti-OC side with their policy against carrying weapons (despite the policy of non-enforcement). In many ways, this is the pro-gun side's fault, because we, the pro-gun community, destroyed the line between "normal open carry" and "political OC activism."
Imagine for a moment that pro-gun folks did not go walking around with unloaded long guns videotaping themselves, and that during the "Starbucks appreciation days" (and other days) pro-gun folks did not arrive armed and in groups. Imagine if instead, we simply purchased coffee from Starbucks (whether carrying openly, concealed, or not at all), brought a business card that said "thanks Starbucks for not infringing on the RKBA" and handed it to the cashier every time we made a purchase. That would have gotten the message across to Starbucks without alienating everyone else. As the cards piled up, they'd know that they have our support, but they'd also know we're not being obnoxious about it.
It would have shown that not only do we appreciate their stance, but that we're "normal people" doing normal things. We just happen to be armed. To me, that makes more sense as far as efforts go to normalize open carry and to support businesses who either support or at least do not oppose us.
IMO - open carrying of a long gun really only makes sense if you're in an area where there is a higher-than-average probability that you're going to run into a large wild animal (generally a rural area). I'd say that a pistol is generally easier to deploy and use quickly if needed for self-defense in close quarters against another person. It's also better in that if you miss your target, the bullet from a handgun won't go nearly as far as one from a long gun.
Not only has the activism backfired re: Starbucks, but it also works against the cause of the normalization of open carry. We're showing that no, people who open carry are not "normal people" but are political activists that want to draw attention to ourselves.
The first amendment guarantees the right to free speech, but it certainly doesn't mean that any business or individual has to provide a person with a platform at which to speak. Starbucks has no obligation to provide any political activist a platform at which to promote their cause. The problem wasn't really "open carry" ... the problem was political activism that involved displaying a weapon, including/especially those who not only carried long guns but carried them either on their side or front, often with a hand on the gun.
Hopefully some of the more "aggressive" folks in the pro-gun movement will learn some lessons from this.
A right requires neither permission nor subsidy. It simply requires that a government not interfere with that right.