From your example - how does the military "unify" a diverse group of people? By aligning their thought processes and decision making. That is, by removing that very diversity.
The two words also mean literally the opposite thing. You can be along a spectrum from one to the other, but you can't have both at once.
I just don't follow your reasoning here. Is it your contention that a new experience deletes or diminishes previous experiences? Or that newly learnt knowledge diminishes that previously learnt?
Surely a new set of common experiences increases the diversity of thought of all the participants? Nothing's lost.