This question belongs on Workplace, not PMSE. The things that make it sound like a PMSE question are red herrings, and not really the central point of the original question.
Not a Project Management Question
The question is not about either the project management profession or about project management frameworks/methodologies. This is strictly an office-politics issue.
The OP isn't dealing with facts, he's dealing with feelings. Specifically, he's framing it with:
[T]his kind of behavior is making us more frustrated and making our employees' efforts useless.
His real questions are all about "managing up" and addressing a political situation from a staffer's point of view. He sums it all up with:
Can anybody tell me how to convince him respectfully? If it is a common behavior, then tell us how to overcome this kind of situation?
Because of the subjective nature of these two questions, answers will be:
- Opinion-based anecdotes.
- A response to an opinion-poll.
- Too broad in scope.
- Possibly not applicable to anyone but the OP or the answerer.
It Would Be Just as Closeable Here
If the question were migrated here without heavy editing, I'd have to vote to close. It was already closed as "Too Broad" on Workplace, rather than as "Off-Topic," and I don't see how migrating it here would make the question inherently any narrower.