Your statement:
The fellow I'm disagreeing with say's,
"the reason that the variable in the calculator for the "dipole feed
impedance"
could be if you want to transform the z to something else, such as 50 ohms."
I don't even understand what he means.

My thoughts: My radio output impedance is 50 ohms, for a feed line I use
RG-8 and other 50 ohm impedenance coax.
If I were to use a folded dipole antenna I think I would prefer one that had
a 50 ohm feedpoint.

Nuff said, KD0FGX