It seems to me there is an actual mental state here as well is between A and B. The mental state is just in respect to the first licensee (let's call him B), who presumably wouldn't have agreed to the contract if WOTC (let's call them A) wouldn't have agreed to make the same offer to everyone else (let's call them C).
Is your opinion that mental state that constitutes an offer cannot occur in that fashion?
My point is that the "automatic offer" is supposed to occur even if W(A) is unaware of it, not a participant in the relevant event, has retracted its own direct offer to licence, etc.
A contract in the common law is, at its core, a meeting of minds over a bargain. Where, here, is the licensor's mind?
I understand going to agency to resolve, but the license doesn't read like it's making anyone an agent so for me it doesn't seem like a strong theory.
The licence is meant to be neutral as between jurisdictions, so I'm not surprised that it doesn't use the language of common law private law. In civilian contract law, as I understand it, it is the intention to establish legal relations that is key, and not any notion of a bargain, and so the "automatic offer" may not be so puzzling.
But when I look around at the automatic offer for someone who is actually bargaining, the person whom I see is the licensee who has distributed the work such that it is received by the new party. And my generic term for a party who can bargain on behalf of another - in this case, a licensor - is
agent.
Without bothering to research (it will be a few weeks before my Agency class)

it does not look like an Agency relationship to me.
Are you comfortable with an automatic offer flowing directly from a licensor that is not connected to any action or event in which they participate? To me it seems very artificial. That's why I find the idea of agency attractive, because at least that puts some boots on the ground - though I find it unattractive for other reasons (eg the potential fiduciary implications).
EDIT:
@S'mon, I added a reply to you after you hit the XP button. It doesn't add much except to reiterate my uncertainty!