All I'm saying is that fans have been wrong about the realism thing, dating back to the early days of TDK. Doesn't matter what we perceive to be the "line" that is not to be crossed. At the end of the day it's Nolan's call, as it should, as it's his world. There was a point in time where people were certain about facets of Joker and Two-Face that had been disproven. Also a near universal assurance that the likes of Bane would never surface in this franchise. Things change.
Honestly, who cares? If he's alive, didn't matter because he's not relevant to the story they're telling. Joker existed at the time of BB but never showed up anywhere. If the final card scene were omitted, would you be questioning his presence in TDK? I never got the need to showcase every individual and setting for every story, as to justify that they still exist.
I personally have no preference as to his inclusion. I'm interested in his revival simply because I'm a fan of the character and it would throw everyone in a frenzy. But if not, no biggie.