I think your mixing two separate things here. The discussion was shut down not because it "might be revealing". It's plain and simple because they think is more harmful to have the discussion at a point when they're in legal trouble (with the corresponding financial penalty) than the argued loss of honest discussion (whatever exactly that means for you). It's because work is not a frigging politics/social debate club. You go to work to do whatever it is you were hired to do, not to discuss topics that may actually reduce productivity on your diverse work force for feeling discriminated.

I understand there's an inevitable social/political aspect of working together, but is not the focus and if you don't agree with the political views/decisions of a company, and you can't get them (through proper channels, your manager, HR) to change, no one grants you the right to say whatever you want in the work place, especially when what you say is widely considered (by the company) as harmful to their interests.