According to Osho, he called his talks the Bible to reclaim a dead, misused word and make it alive and juicy again. By setting a living, experiential Bible against the Christians' dry, dogmatic one, he dramatizes the contrast and invites seekers to choose vitality over bones - presence, juice, and direct taste over secondhand tradition.
He used the word Bible to show the difference between a dry old book and a living teaching you can feel now, so you choose life over dogma.