Well, we're all pussies, that's why.
When a bat flew in Bruce Wayne's open window, he took that as a sign, an omen. He became a creature of the night. He became The Batman.
But when a couple in Chicago's Lincoln Square find a bat in their apartment, they don't become Batman and Batwoman. They don't fight the pervasive crime that infests the corner of Lawrence and Western Avenues. No, they trap the bat in a bucket, call Chicago Animal Control and discover that the bat has rabies. And now, they are undergoing medical treatment for rabies. Bo-oring.
Maybe that bat was radioactive and, if it had bitten the man, he would have become a real-life Man-Bat. Or if the bat had been bitten by a moth and then the moth bit the woman, she would have become Luna Moth. The possibilities are ENDLESS.
Well, the possibilities are endless if you're not a pussy who is afraid of rabies anyway...