The "Socrates" in the so often used proposition "Socrates is a human" is, unless stated otherwise, always meant to be an example. It is not meant to express : "Socrates as Socrates is a human". It is meant to be completely equivalent with "Plato is a human", "Melissus is a human", etc.
An thus the proposition "Socrates is a human" is, it is true, a proposition about an individual, but it is undecided as to precisely which individuum the proposition is about, because 'Socrates' is here only used as an example, as a case among many cases.
The proposition is therefore generally individual, but not particular.
"Socrates as Socrates (and not as Plato, Melissus, etc) is a human" refers to something particular, and so to something contingent.
A generally individual proposition does not refer to something contingent.
Entities like The Second World War, or The last Dodo bird, are in themselves exclusively particular : they cannot, each of themselves, serve as examples of identical cases. They are, like Socrates, unique. But, also like 'Socrates', they can figure as examples, but only when they are seen as individuals of a species : Socrates is an individual (case) of the species MAN, the Second World War is an individual (case) of the species WORLD WAR, and the last Dodo bird is an individual (case) of the species LAST BIRD.
In contrast to these cases we can consider an individual here-and-now electron as an example of identical cases, because every electron is intrinsically identical to every other electron (where 'other' here means an electron at a different time or a different place or both).