Negative G
You are completely misreading, misunderstanding or misrepresenting the situation. The aircraft is designated in the POH as a PA23E-250 (where the E might be a D or an F).
In flight plans until about 3 or 4 years ago it was allowable to put either PA23 or PAZT. The edict then came out from ICAO that we had to put PA27. I rather suspect that this requirement came from Route Charges, because an Apache isn't chargeable but an Aztec is (but I have no evidence of this.)
Once the FPL says PA27 ATCOs will tend to use that designator, particularly if, unlike Chilli, they are not familiar with the type, though I agree that it is more helpful if they identify us to others as Aztecs. When I check in on frequency I always call myself an Aztec, in the hope that the ATCO will do the same.
But one way or the other this has nothing to do with people being nerdish with Piper numbers. It is a change of rules imposed by ICAO.
If you don't keep up with the situation blame yourself, not those of us that do.
W