No, it's not valid. The only reason it would be done is for deceitful reasons. Therefore, not valid.
Keeping it private here means private from external companies that should not have access to that data, not employees. This includes competitors, M&A targets, and investors who have not yet invested and should not have access to the books.
I do however strongly believe in tempering expectations, it's wrong to try to retain people by thinking they have more than they do.