Biological diversity doesn't mean nor imply diversity within species and/or groups. Rather, it means diversity within every conceivable environmental niche which in turn is the primary driver of speciation. That is, the very definition of in/out groups ie those that can no longer reproduce.
Regardless of these mundane semantics, the real issue - as I pointed out above - is the ability to identify enemy tactics and techniques. The wholesale brainwashing and gas lighting of entire populations is the real marvel. I would think prospective academics should study that phenomenon, rather than the obvious refutation of the ridiculous "diversity is strength" slogan.
Ah, yes. That's good. And I'll add my objective: to preclude pendulum swings. What makes a society inclusive and exclusive while retaining its identity is not a one-sided affair.