Now obviously, what he did was injudicious. If you are a white male and suspect a diversity program is going to fail (and there's a lot of evidence that many of them do fail, sometimes even with negative impacts on the people they are meant to help) then you would be wise to shut up. The same would be true if a religious owner asked employees what they thought of their religion. It's best to just avoid disagreeing without showing too much interest.
Sure, that makes sense in the short term. But if everyone did this, over a long period of time, two things would happen:
(a) Diversity programs would at some point stop being ineffective.
and
(b) Identity politics would achieve cultural hegemony.
I agree that it would be wise to shut up if doing so had no long term effects (as in your example of a manager asking about religion), but that clearly isn't the case here. And in the case of (b), I would say that long-term effect is extremely undesirable, for both businesses and individuals.
