Open-carrying an AK to a coffeeshop in defense of the Second Amendment is like speaking in favor of the KKK to defend the First Amendment.
Yes, both ought to be allowed as a matter of law, but don't be surprised at the social opprobrium. Just because I'll volunteer to defend your rights in court doesn't mean I'll let you have dinner at my table.
I pretty much agree with your comments.
If a business allows one to carry within their confines, do so concealed, and be happy with the fact that you COULD have done so openly.