This is not a property rights issue versus RKBA issue. It's a property rights versus property rights issue, as well as a property rights issue versus discrimination issue.
First, businesses are public corporations licensed by the state. The federal government and states restricts discrimination on employment and public accomodation based on race, national origin, religion (which is a choice), creed (which is a choice), and sex. Some state go further and prohibit sexual orientation discrimination. To argue that a corporation, chartered and licensed and rather heavily regulated under state laws, has the same rights or more than, say, your private home and land, is patently false.
Second, what about the property rights of the worker? You have to remember that in some states, your car is also considered your castle. It's that way in Louisiana, New Mexico, now Florida with it's new stand your ground law. Your car is your own private property. This is one of the reasons I distrust at-will employment because there are a few companies feel that they can micromanage everything in your life, and with the state of the economy being the way it is, it's sometimes either go with them, or lose your house, your health insurance, etc etc etc.
Third, I believe that firearms ownership status should be a protected class, if religion, creed, and smoking outside of work (in some states) are protected too. You have people like Toby Hoover of OAGV demanding employers fire CHL holders, or prevent CHL holders from obtaining work at all, even if they have no intention to carry at work or to use any such parking lot exemption, for merely possessing a license to carry outside of work. They went from just demanding gun control from government to making us perpetually unemployed, homeless (being unable to rent an apartment, see my
Archstone post), taking our children away from us via CPS, etc etetc. How does it benefit the nation as a whole if we have to rely on government assistance to get by? How does it benefit being unable to pay their debts until their credit is ruined and they have to file bankruptcy and lose everything? The only people who benefit are the anti-gunners who want to send us a message: Give up your guns, or we'll take away your jobs, your insurance, your housing at rental places, and your homes. The situation in Oklahoma, and what's about to happen in Michigan, is us, to use the term "shooting back" at such inane hatred and stupidity.