When Batman was drawn for the first time, he had purple gloves. Nothing else on him was purple. In retrospect, it looks really silly, but it was the style at the time.
Stories and characters grow and change over time. Superman couldn't fly for 3-5 years after his creation. Huge swaths of Star Wars mythology were created whole cloth from single lines uttered by characters--George Lucas, Dave Filoni, and others have spent the last 45 years backing new stories into neat spaces in the Star Wars universe. Doctor Who has changed numbering methods for the Doctors more than once in its six-decade history.
And this doesn't just apply to modern nerd fare. Humanity's many forms of mythology were assembled through centuries of storytelling and oral tradition, and there is no order to them, no canon per se; you would go insane if you tried to organize them because they were never made with that in mind. They were stories meant to teach lessons, impart wisdom, or entertain--the internal logic of the story was tertiary at best.
In all cases, these stories were made up. They're inherently flexible. But there seems to be a belief in fandom today that what has come before is sacrosanct--while also being incredibly selective about what we want to pick from.
Going back to Batman, a recent episode of Harley Quinn (Season 3, Episode 8) digs into this in the most fascinating way. In this installment, Harley ends up in the mind of Bruce Wayne, where she finds the memory of his parents' murder on an infinite loop. Hiding inside the mind of the intimidating vigilante is the young boy who watched his parents die and somehow believes himself at fault for it. After Harley breaks the loop--temporarily at least--she and young Bruce walk down a hallway
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