That letter raises red flags from as high a level as you'll ever see in a company such as Cathay.
Managers will not raise such issues, because the very willingness to do so would have disqualified them from management in the first place. That is a corporate culture issue applicable to many organisations, but in this case particularly to Cathay. Mid level flight ops managers in many (not all) western airlines have a dual role; they shovel $hit downwards but at the same protect the line drivers from the worst of it. When they do their job properly, letters such as these aren't required.
Respect for the individuals who wrote it. Respect for the individuals who signed it. Shame on the individual who leaked it. And shame on the managers who made this letter necessary in the first place.
The canary-bird has sung its song.