When your call about fatigue is genuine, you will not be bothered if it is questioned. Of course when this is abused it is a different story.
I couldn't disagree more.
If that is so, why are so many pilots so weary of mentioning fatigue?
If it is a prior to the start of a flight, the cause of being unfit for duty is irrelevant.
If it is an in- flight onset of fatigue, then obviously some kind of report will be needed so fatigue does need to be mentioned, but should never be questioned.