This is... actually really obvious? That's what the Martha moment was, humanizing Superman to Batman (amongst a couple of other things).
And that moment fails, precisely because Superman ISN'T HUMAN. He's a nigh-invulnerable god-man who had a huge hand in leveling an entire city and ending hundreds of lives, and yet Batman decides "men are still good" despite the fact that, you know, Clark IS partially responsible for all that death and destruction, is still extremely violent and dangerous, and who knows how many thugs Batman killed or mutilated who also had mothers named Martha. Batman created a lot of widows, orphans, and grieving mothers...
Outside of the brand (which he doesn't exactly discard...), Batman still seemed just as murder-happy and lethal after his faith in "humanity" is restored... even though a being from across the stars died to stop a rampaging monster created by a deranged, evil, and very-human megalomaniac.
Every time I remember that Martha moment, I just completely fail to take anything seriously.