Just think of SHAZAM as the precursor (and much more effective version) of that inane COEXIST sign. Nice intention, you get what they're going for, but ultimately feel-good meaningless without the willpower to actually see it through.
And, the overanalyzing part of me connects it further with how much attention the Wizard Shazam had to pay towards finding the right champion. Just as how not just any soccer mom that wants to speak to your manager will live up to the COEXIST bumper sticker on her Subaru, not just any mortal would be right for the powers of SHAZAM.