Because if you are a high level executive and you are transparent on those things, and if it backfires, it will backfire hard for your future opportunities, since all the companies will view you as a potential liability. So it is always safer and wiser option to not say anything in case of any risk of it backfiring. So you do the polite PR messaging every single time. There's nothing to be gained on the individual level of being transparent, only to be risked.