All right, then. You Asked.
In fact, it's delightful to answer, since this is possibly one of the most misconstrued scenes in the story. Might be a blessing to have the information examined in a less hysterical light - 
- please note, Angela, the more rabid responses have been elsewhere, and not brought "home" as it were, to this board. I appreciate your courage, for that. (elsewhere, my hands are quite tied, and you have freed me, as it were.)
I will do my best to respond, bearing in mind that the story will cover territory that will vindicate everything, quite well, without my intervention in the direct authorial voice.
Next, we will all note: this is a work of Fiction, and though some ideas have been drawn from some esoteric sources, and while some folks have, or claim to have, experience that may parallel what appears to "be" on any given page, let's not equate this stuff with what IS real - although given a quantum universe, what is real cannot be separated (quite) from the point of view of the observer. I am author, but not authority, if you can catch the subtle difference.
This said, here goes:
The purpose of this scene was manyfold.
Primarily, it was the most graphic example I could create that would unfold the ENERGETIC template that occurs between an attuned crown prince, and the land's energetic patterning, or electromagnetic underpinning.
Before we run off screaming, why This way, let us take due note: NONE of the characters present in that scene was pleased IN ANY WAY with what occurred. So it could be said, their feelings and yours ran in parallel.
If Kharadmon (and through him, Dakar) regarded the event as necessity, the reason for that will unfold with more clarity in due time - although the latent forces in the land's lanes, UNDISCHARGED, was certainly and plainly going to cause ecological disaster, if not more - that exigency was pretty well delineated on page - I can easily concede the possibility that this point becomes eclipsed, in the heat of whatever predisposition a reader brings to what's just happened on the page.
Next, this scene "stages" the foundation for one of the climactic scenes in Stormed Fortress.
WARNING HEREFORWARD - direct spoilers for earlier volumes may follow:
This scene, very dramatically and neatly, shows the reader the importance and the mystery of the crystal left with Koriathain, and why Elaira can't just "ask" for her vows to be rescinded with Fellowship help. There is a gentle restatement of an earlier point, that not even Sethvir understands all the ramifications of this conundrum.
If one sets sexual bias and the squeamishness born of personal and/or societal taboos (which have their reasons, I am not arguing that) the underlying points would become quite clear.
The books STILL HAVE NOT addressed what exactly happens when a crown prince receives Sanction, and the attunement to the land - or what a High King, crowned, really means, or how such ranked service functions. The books will unfold this - look to future volumes. This scene is just the "opener" as far as how IMPORTANT such a binding can become.
This is the scene that begins the fracture between Dakar's past, and his future - which road his acceptance of responsibility will finally take. Heretofore, he's been either blind, or divided. In choosing Kharadmon's stance, that was a defining moment, whether he recognized it or not.
We see that Arithon and Elaira are not unbiased, either, that for them, the greater picture is of less importance, at this moment in the story - and that the meaning of Arithon's name as Fate's Forger will continue to play, as he challenges the lines drawn before him with innovation - but that he sometimes could fail to see everything coming.
This scene was the most graphic I could imagine that would show just how INSIDIOUS the Prime's plotting had become - that the trap she had spun almost slipped straight past the Fellowship Sorcerers' vigilance. Or did it???
In all respects, the stakes were deepened, and heightened - and it's now quite plain that underneath the characters' actions and interactions, there is an energetic law and pattern at play - hard to explain without a lot of dry exposition - far better to see it in action. A lesser scene would have been too easily disregarded, or forgotten, or written off as of no importance. When the pattern comes round again, you will not have forgotten - the act itself was the lesser point - the greater was the implication drawn.
That Kharadmon would have ever contemplated such an intervention - imagine the stakes? When once he loved, also, and you have seen his gallantry when he interacted with Elaira, in Fugitive Prince. Might ask WHY he thought the importance so high - and then watch for the unfoldment to see.
This scene spring-boarded Arithon's aversion to ASK Fellowship help - and why he ran quite such a high risk at Etarra in subduing the Gray Kralovir…YES that scene ought to scare you silly!!! It did me. In spades. It's an ugly concept, horrific, and will stage into the handling of the two more apparently refined, and insidious cults that are still left on world.
You are MEANT to feel viscerally in this scene…doesn't matter what society you are from, or what those human systems deem acceptable - the emotional violation of ALL the characters involved, vs the exigency of what the Fellowship Sorcerers were forced to stand by in the moment - this was actual the crucible.
There is a contrast drawn, too, with THIS event and later ones in Stormed Fortress, set against that climactic scene for Arc III - you'll need to read the story further, for that, I will not risk spoiling it here.
Anyone who does not wish to go on, or who is so offended by this scene - so be it. I don't choose your reading - you do…but I would ask, is there anything WORSE than the scene at the Havens, or Tal Quorin, or - well name any of a dozen??? And neither of those were done frivolously, either, as later books bore out quite nicely.
My applause to this group here for discussing this topic with the respect and insight that both awes me, and makes me appreciate you as my readers - thank you!
My closing point: you are NOT MEANT TO BE RECONCILED with this scene - on any count! That was its purpose - just as the scene at the Havens, or what occurred in Daon Ramon Barrens, under Jieret - these scenes were never meant to rest well, or feel good - they will, however, drive the characters to unveil further strengths and depths. And rise to new changes. THAT will be well worth the waiting for, I can quite earnestly hope.