What is being "preserved"?
What does a private proprietorship gain by acting against our Constitutional mandate that the RKBA's shall not be infringed?
They gain the right to be secure in their private property. I believe that few will choose to take a stand against firearms in the face of competition from corporations which are not allowed to infringe the right. You may not carry on my private property even if I choose to carry on business on that property.
There is no right to incorporate and be granted limited liability. That is a legal privilege granted by legislatures based on expected benefits to the whole people. One of the benefits can be the extension of the right to keep and bear arms to corporate parking lots.
Look at what you just said here. It shows a profound lack of understanding of the nature of the Constitution.
Let's say you own a store. And some ANSWER types come into your store and start chanting anti-American slogans.
Using your logic, if you kick them out of the store, private property, you would be acting against our Constitutional mandate that freedom of speech shall not be outlawed.
The Bill of Rights is a prohibition against government action - not individual action. Private individuals and companies have the right to dictate who can use their property and how it can be used. If you don't like their terms, don't work for them and don't give them business. But you cannot take your rights and force them down someone else's throats at the expense of their Constitutional property rights.