It depends what your company procedure is - if you company procedure is to PA the whole aircraft (as mine is) then you need to use PA1.
Your role as an onboard manager is to follow the documented procedures whereever possible not adjust them because you don't agree with them - if you don't agree with them then you need to submit relevent reports in the hope of getting the procedure changed.
If your companies procedure is to use PA1 and you decide to use PA2 for whatever reason and a J class pax gets injured in turbulance & claims they didn't know the seatbelt sign was on due to no PA and takes legal action against your airline - as you're the individual who didn't follow procedure you'll have a whole lot more issues then a tired pilot!
As for the "dobber"... well that's a whole other issue - that being the case there appears to be a culture issue if you have crew dobbing directly to management as apposed to highlighting their concerns directly with you or putting in a safety report.
At the end of the day I'd assume that as the onboard manager you or your second in charge would make all the PA's anyway which makes me wonder how the other crew even realised?