You really don't have to have them be a presence though, and when the New 52 brought the demigod origin into place the Olympians became the A-plot and dominated the book. So that reasoning doesn't hold up based on what has been published.
Explaining why Hippolyta would choose to sleep with a misogynistic abuser and rapist like Zeus requires a way bigger explanation than the goddesses providing blessings. They dish out blessings to mortals they like all the time in Greek myth. It's not a difficult thing for audiences to grasp at all.