I agree revenge and anger may be a large part of the story, but I think the idea of revenge is the Bad Ending of it. Or, more specifically, I believe the moral is that Revenge Won't Help. A cycle needs to be broken.
I like the analysis of Hera's Snakes too, but I also think a lot of people focus too heavily on the idea of the snakes being the ones sent for Herakles or something similar. I think the symbolism present in both Hera and the Snakes is far deeper than just 'unhappy with circumstances and wants revenge'.
There's two parts to it though. The first being Hera, and the second being the Snakes.
Hera is... complex. She's a complex figure due to a variety of reasons, but one of them is that despite her age, not muuuchhhh exists of her, whether mythologically or religiously. What we DO have is largely entertainment-based, meaning her personality is different from how the greeks would've seen her. There's also the modern issue of modern interpretations of Hera being.... not great. She is, like you said, a goddess of childbirth and marriage, but she is also the Wife of the King of the Heavens. The idea of her as Queen of the Heavens came later, so while that does end up as a part of her ideology, it wasn't original to Greece (and I believe was Roman?)
Anyway, the veil is incredibly important imo. The childbirth could also be seen as important given the fact that she will turn into Kyklos herself (thereby giving Birth to a new Kyklos, not to mention flower symbolism often equating to Fertility in mythology, and Hera having flowers as an epithet, among other things) but the marriage is what it really is referring to. Maybe not a literal 'shes getting married!', but certainly some type of metaphorical hieros gamos, or a bridge between the Human World and the Anomalous World. She is literally bringing these two worlds together as a human thrust into this world and given a power very similar to a stigma. She's not a ghoul, but she has ghoul traits. She's a human, but she is deeply non-human. The veil, which then becomes a ring, is a solidification of her role as the bridge between these two worlds, and a symbolic marriage of the two of them into one person. It's also probably not a coincidence that there's moon symbolism associated with MC through her name (Luna). The whispers of the new moon is also the ghoul symbolism, and it is, in addition, attributed to Hera.
Therefore they name her Juno (a juvenescendo, the name signifying a thing that is new or grows young) from the nature of the Moon; and they call her Lucina (as it were bright or shining), and they are of opinion that she helps women in their travail-pains. (Plut. Quaes. Rom. 77)
The relationship she has with Darkwick is also very similar to that of Hera and Zeus. While Hera is consulted on things by Zeus that he wouldn't discuss with others, and while she is trusted by him, she has far less power than he does, and can (and does) get into trouble with him. It's to the point where she may be Captured if she disobeys (and she is captured at some point in her mythology).
And all of this doesn't even mention the Trojan War or how she went against Zeus in that, or how she's revered in many different places as a protector of women, or her connection to flowers and cycles and rebirth, or her veil being a big part of her, how five gods are considered by Plutarch to reside over marriage, how she later is given the power of presiding over prophecy, how her epithet for that relates to holding her hand over something..... I could genuinely go on and on and on.
Snake wise, it's very similar. There's so. so much about snakes. so much to say. too much to say in fact. i would die before i could say it all. Snakes are not only associated with evil and revenge, but also healing and protection. They're underworld creatures (with some gods taking on Underworld Forms, like my best friend, Snake Zeus, Zneus, Zeus Melichios) but they're also associated with Olympic gods (Apollo, Asclepius, Athena, etc).
There's also the Ouroboros, which is the most well known cyclical symbol. In my opinion, the reason it's Hera's Snakes specifically is because it, at first glance and through reputation, harms and kills the wearer and those around it, it is actually protecting them in the best way it knows. It keeps those with intent to harm away, which is also what things like Athena's gorgon shield does. It protects MC in order to solidify her union between the human and anomalous worlds.
Anyway, I could ramble forever abt all of this, but this is. Already way too long I'm so so sorry. I'm so sorry.
