You make the same valid argument as the Texas Lawmaker whose parents were murdered in a restaurant while the three of them were eating. A gunman came in and just starting shooting. Her gun was safely stored in her glovebox.

And while there should never be a law that restricts or prohibits your right to defend your life, there is nothing wrong with employer restricted your rights while under their employment. Just as Disk Jockey's clamor about Free Speech, this is not an action taken by the government against you; this is you volunteering to retard your rights in order to gain employment with a specific company.