This same principle holds for others on their property, even if we do not agree with it. Else, your proerty rights...and therefore your liberty, or worthless in the eyes of any such law founded upon their infringement (and we already have a bunch of those) and in the eyes of any such citizen who feels free to trample your rights on your property and do whatever the hell they please irrespective of your desires.
What really keeps us free is the morality that allows us to recognize other's rights and respect them. As I said, your ability to bear arms is not infringed...you can choose to boycott me and my property and remain armed, you can choose to ignore my just requests and suffer the consequences when doing so on my property.
Now...I personally would not, as a company, make such a demand. But these people are. Boycott them and their business, boycott their employ, as Squantos said. But do not use the force of law and the government to demand that they do things your way on their property. Such a premise is an awful, and dangerous two-edged sword.
My Father is a hidebound Southern Baptist. His Daddy was a preacher and they grew up hating Catholics. My Father was so strong in his beliefs that he refused to go to his daughter's wedding when she married a Catholic. (His Son-in-Law is now one of his favorites).
Now suppose my Father owned a large factory. He issues an order than no St. Christopher's medals can be left in the employee's private vehicles in his parking lot. The Catholic employees don't like it but decide to not cause trouble and just put them in their glove compartments prior to parking.
Now Daddy finds out they still have them in their glove boxes and fires them all.
A legislator finds out about my Father's outrageous demands and passes a bill that they can keep them in their cars if they want.
That is an almost exact analogy. The only difference is the right to keep arms is potentially life saving. While I doubt even the most devout Catholics think the medal itself actually protects them.