I think it comes down to the anxiety fans feel of whether:
A) he will flatter to deceive in the end and set us back further.
or
B) be the franchise QB that may takes us to a Superbowl.
Due to his inconsistent play..
..at one moment he seems to show the REAL potential for A, another moment he showed was the REAL potential for B.
Everything is viewed through this 'lens' of extremes.
(To clarify* he CAN be consistent on drives but will often make a mistake like an INT, FUMBLE or will be off on some throws and off on some drives that ask the question: which is the REAL Josh Allen?)