The Wonder Woman (2017) mythology is based on the decline of mankind marked by a series of ages, the Ages of Man. Hesiod wrote about this first:
First of all the deathless gods who dwell on Olympus made a golden race of mortal men who lived in the time of Cronos when he was reigning in heaven... They dwelt in ease and peace upon their lands with many good things.
Works and Days 109 ff.
Then they who dwell on Olympus made a second generation which was of silver and less noble by far.
Zeus the Father made a third generation of mortal men, a brazen race, sprung from ash-trees ; and it was in no way equal to the silver age, but was terrible and strong. They loved the lamentable works of Ares and deeds of violence;
The film gets this right in that it is love of Ares/war that war is a major element of the decline.
Interesting also is the next generation:
Zeus the son of Cronos made yet another, the fourth, upon the fruitful earth, which was nobler and more righteous, a god-like race of hero-men who are called demi-gods, the race before our own, throughout the boundless earth. Grim war and dread battle destroyed a part of them, some in the land of Cadmus at seven-gated Thebes when they fought for the flocks of Oedipus, and some, when it had brought them in ships over the great sea gulf to Troy for rich-haired Helen's sake: there death's end enshrouded a part of them. But to the others father Zeus the son of Cronos gave a living and an abode apart from men, and made them dwell at the ends of earth. And they live untouched by sorrow in the islands of the blessed along the shore of deep-swirling Ocean, happy heroes for whom the grain-giving earth bears honey-sweet fruit flourishing thrice a year, far from the deathless gods, and Cronos rules over them; for the father of men and gods released him from his bonds.
An islands "untouched by sorrow" certainly sounds like the depiction of Themyscira, and "Cronos rules over them; for the father of men and gods released him from his bonds" is suggestive of immortality, an attribute of the Amazons who dwell there.
However, in the ancient canon, it is Zeus himself who is mankind's main antagonist:
And Prometheus had a son Deucalion. He reigning in the regions about Phthia, married Pyrrha, the daughter of Epimetheus and Pandora, the first woman fashioned by the gods. And when Zeus would destroy the men of the Bronze Age, Deucalion by the advice of Prometheus constructed a chest, and having stored it with provisions he embarked in it with Pyrrha. But Zeus by pouring heavy rain from heaven flooded the greater part of Greece, so that all men were destroyed, except a few who fled to the high mountains.
Bibliotheca (Apollodorus) 1.7.2
so Ares in this role would seem to be an innovation--it is certainly consistent with his character as the god of war. This can be taken as a metaphor for the extinction-level weapons (MAD) that are a unique characteristic of our era, and WWI as the "war to end all wars".
Man as the instrument of his own destruction, from the standpoint of the species, is a common characteristic of many modern mythologies, including Skynet and Zombies. Ares merely provides us the tools.