Zeus: what his authority actually protects
Zeus is probably the clearest reason we shouldn't assume these two universes are doing the same thing with the Greek gods.
In Absolute Wonder Woman, Diana grows up dealing with the consequences of his authority. Prometheus is still being punished. Pegasus has been killed. Diana can help Prometheus and give him some relief, but she knows that cutting his chains doesn't permanently undo what Zeus has imposed on him. Another eagle can come. There is a whole arrangement behind the suffering, and helping one person doesn't automatically dismantle it.
That makes her promise to Prometheus important. She wants his help with a weapon she will use to defend humanity, even against the gods if necessary. His gift becomes part of Nemesis. Somebody suffering under divine punishment helps equip a person willing to challenge divine cruelty. The relationships behind the weapon matter as much as what it does when she throws it around somebody.
Grimm gives Zeus a different role in Goddess Inc. Venus says he ended the old arrangement in which mortals were subservient to the gods and stopped the gods from being worshipped. She remembers that as a loss. The adoration belonged to her, as far as she's concerned, and she wants it back.
So in that conflict, maintaining Zeus's arrangement means preventing a return to divine domination. That doesn't make every choice he has ever made good. We've already covered how ugly his family relationships can get. It does mean we can't carry our judgment of Absolute's Zeus over to Gregor and assume we know which side of this particular fight he belongs on.
That reversal is the part worth comparing. In Absolute, Diana's defense of humanity includes being prepared to oppose the gods. In Goddess Inc, Zeus is fighting a faction that wants humanity put back beneath them. Both books have gods fighting gods, but the dispute has a different shape.
The names and the lightning are familiar. The reason someone deserves to be opposed has to come from the story we're actually reading.
Zeus: what his authority actually protects
· Absolute DC and Grimm mythology comparisons