Yeah I am starting to think it's a free book, available at all stores which also sell the starter set, which provides the character generation rules and introduces the Adventurer's League.
It's not in the starter set, because it's outside the set and available for free to anyone who wants it, so it can reach an even larger audience than just the starter set customers.
They even mention at the end of the Adventurer's League article, "Over the next several weeks, we’ll be exploring more aspects of the D&D Adventurers League and its play programs as we head towards launch in August. We’ll talk about how you can get involved, character creation rules, factions, and much more. "
That would make sense out of some things that have not made sense thus far.