Right, and the whole reason it's an issue is specifically because Starbucks asked not to be dragged into it. Those folks ignored Starbucks explicit wishes by flaunting their signs (which, you're right, is exactly what they are), right in the middle of Starbucks. They could have OCed a pistol properly all day and never incurred any reaction. But, no! They had to bring their signs onto private property, when the owner had asked for no political grandstanding.
Those folks deserved to get slapped down. It's only a shame they had to go and get the rest of us slapped, too. For this, they deserve to be shunned, and I'm starting right now.