Batman is a human being. A human being reduced to a skeleton and a costume. Which they buried.
And, again, coming back from the dead has NOTHING to do with being clever.
Far more clever people than Bruce 'I work with magicians, but insist magic doesn't work' Wayne are still languishing in the afterlife. Far less clever people have come back.
Rational absorption of the concept that sometimes the dead come back involves not being too terribly surprised when someone does to come back.
Insisting that someone whose corpse EVERYONE had seen - whose headless corpse you had seen not long ago - is not rational. It's pure insanity.