OD&D did not call itself a "role playering game." The box cover says
"rules for fantastic medieval wargames." The text itself refers to choosing a "role" as a combination of race and class: "players must decide what role they will play in the campaign, human or otherwise, fighter, cleric, or magic-user." What I can't figure out is who called this activity "role playing" first. It's misleading because it suggests that the player is an actor in a story, which is not what OD&D was actually about. It was just a game, and people played to win.
Ron Edwards explained that the rules were revised and scattering among publications, so a lot of people made it up as they went, playing for make believe instead of to win.
AD&D was Gary Gygax's response to this, which was not received well by those who were told they were playing it wrong.