How about: "Because I say so, and it's my $odding airfield."
I liked the comparison with the pub. You create a hassle for no good reason, and people move their custom elsewhere.
Putting a good reason in the AIP for a PPR might help in improving the customers' (incoming pilots') understanding and encourage them to participate in the better functioning of the airfield.
I'm not encouraging pilots to fly into a PPR field without obtaining prior permission. That is indeed poor manners (or even poor airmanship). I'm merely saying that, if two airfields would serve my purpose, and one is PPR for no good reason, I will give my custom to the other.
I wonder if there's a correlation between those who don't do checks, and those who object to phoning for PPR?
You obviously have no idea about correlation, or any other statistical parameter for that matter. While I always perform proper checks, I do take exception to being forced to perform a de facto needless action.
Filing a flight plan also can take care of the PPR.
No it doesn't. How do you know the flight plan reaches the aerodrome operator ?