It's really quite simple.
Can you pick it up in your hands and carry it to your mouth? If you cannot (for any reason other than "it's a really big one") then it is not, by any sensible definition, a pie. A pie is self-sustaining and stands alone, proud. It does not require third party support from some party-sized casserole dish.
Stew with a hat does not equal pie.
I associate myself with those remarks.
End of thread surely.