Inevitably someone will ask "Why lie about this?"

If I tell you that you are an insignificant lifeform on an insignificant planet in an insignificant part of the universe and that there is no creator of your world, but the pseudo-scientific "Life appearing out of non-life", the highest authority in your mind would be me.

After I've programmed you thusly I am free to tell you any nonsense which would benefit me at your expense, and you wouldn't even think to question it. Mind enslavement. Hiding the true earth is playing god.