At least on the fact of its text, the licence does not purport to bind non-parties.
Quite right.
But then, WotC is under no onus to point out that terms don't apply unless you agree.
As part of a license, they do not have to preface every line with, "If you agree to this license..." for example. That is assumed in legal terms. But it is not assumed in normal conversational language. So, to a layman, a term that reads "X is true" looks like a statement of fact, when it is actually a conditional - "If you agree to this license, X is true."