The topic of discussion was the fact that we're trying to encourage employees to share salaries with each other. They wanted to try to argue that it was against the "corporate culture" and "Attitude" and that it creates an "uncomfortable work environment" where people who might not be willing to share that information are feeling pressured to, and compared it to sharing medical information.
Get it in writing. No need to say the real reason why - just see if there's any way to get them to repeat that over email.
This is basically the one thing that a state labor board is useful for and you'll be happy to have it in your back pocket.