But according to one theory, there may be an in-universe explanation for all this. Remember, we're not actually seeing an adaptation of the book The Hobbit by J.R.R. Tolkien. The first film, An Unexpected Journey, begins with Bilbo writing his memoirs ...
New Line Cinema
New Line Cinema"... in a Shire far, far away."
Meaning that the three movies we're about to watch could in fact be a representation of Bilbo's story from his own perspective, and not the objective POV of the original novel. So the events we see onscreen are being filtered through the brain of a senior citizen trying to recall his youth and, well, maybe embellishing a bit to keep the kids reading.
Like, maybe there was no giant white orc at all, but Bilbo knew the pacing of the real story was off a little and decided to spice things up. Hell, for all we know, Bilbo's literary agent kept convincing him to punch up the action so it could compete with Hobbit John Grisham.