Unfortunately that isn't true. Businesses have a right to refuse service for a wide variety of reasons. Like you said though those protected classes are illegal to discriminate against.
That is why you can have rules, like "no shirt no shoes no service". So in this case it is if you bring a gun you will be asked to leave.
Although now if that store was ever a victim of a robbery I would bet the response time is very slow....
"The reality is that we have the tools to create a much better, richer society for everyone. But the people at the top would prefer a worse, poorer country, if that’s what’s required for them to stay completely in charge."
This is so true. The world as it is now is so depressing and the ones at the top like it that way.
Very good article!