Pretending that transparency always has only good effects is clearly nonsense; but I think that pretending that the lack of transparency ever has good effects is suspect at best.
Your Character Is What You Do When Nobody Is Watching
Your chances of having a problem from stuff being leaked is greatly reduced if you aren't doing shitty things to begin with.
Not that I think that's what motivated this "whistleblower".
It is naive to think that a bad actor cannot craft a falsehood from a subset of truths they select that you've chosen to make public.
It can't both be the case that transparency ever has bad effects and lack of transparency never has good effects: pick one of the bad effects of transparency and introduce "lack of transparency" in its place. Isn't that bad effect now gone? Isn't that a good effect of the lack of transparency?
Granted, any time that transparency leads to bad effects, lack of transparency would presumably have led to the lack of those bad effects, and so be good, at least indirectly. A one-time lack of transparency can perhaps be appropriate.
However, a culture of lack of transparency is not the opposite of a culture of transparency, and those are the two poles I really see us discussing. A culture of transparency can lead to problems, but can also lead to good things (or at least to the exposure of bad things so that they can be addressed); whereas a culture of lack of transparency always will lead to problems, and any temporary good results from its imposition will be overwhelmed by its long-term ill effects.
Which isn't to claim that all dissenting views are good. But when you are an industry that is having a hard time with minority views, forcing the minority to take center/public stage at all times is actually somewhat counter productive.
Put differently, if you are going to encourage transparency for communication and decisions, you have to take extra care to not punish good faith mistakes.
So yes, lack of transparency can have good effect.
if you're describing your past experiences, you should definitely level that skill, especially if it makes you uncomfortable.