The Kinslayings, an escalation of Pointless Violence
One thing I love about how Tolkien portrays the Kinslayings of the Feanorians, is how they tell a tale that ties into his ideas of how evil is an influencing force that will destroy a person over time if he ever tries to justify wickedness for "the greater good".
And he should know, as a man who fought and survived WW1, one of the most pointless wastes of human lives there ever was, justified by "othering" men with the same roots, religion and values as oneself in order to justify killing millions of them, as well as sending off an entire generation of young men to die for these hollow ideals, he would know a thing or teo about justifying wickedness "for the greater good".
The start of the first kinslaying is the only one that is arguably "Necessary" from a brutal, utilitarian perspective.
The Noldor need to get across the sea, meaning they either have to procure ships, or they have to walk across the deadly land bridge in the north.
So with these two options, if they choose to sail, they have 2 options. Either they get the ships that alreqdy exists one way or another, or they take the painstakingly longer road of making new ships themselves.
Now this second choice doesnt exactly line up neatly with an event that came later, but it very much brings to mind how during the war of the last alliance, the gathered forces of Arnor and Gil-galad spent years painstakingly making equipment, procuring food, and making battle plans for the campaign that would lead them to victory.
Now they didn't exactly have any easy options then like the Feanorians do, but it shows what Tolkien's message is. The hard road, with work, preparation and planning is the way to go.
But of course Feanor was not one such.
Instead when he was not allowed to borrow the ships, he and his responded with threats, then murder, as they slaughtered their own until just now friends and "Countrymen"(In as so far that they were all elves of Valinor".
It is a brutal, heartless afair that sours any and all goodwill they might have gotten from the Valar if they had done this in a better way, and has massive consequences for all elves who now find themselves barred from Valinor.
But that's not where it ends, because what follows is Escalation.
Feanor and his sons have gone down a path from which there is seemingly no going back from, and so, deciding that if he uses the boats to go back to valinor and ferry across the rest of his own people, his subjects, the people he hinself lead to kill their own comrades and friends, he leaves them to their own fate and burns the ships he stole down, in order to ensure that he would remain the unchallenged leader of the Noldor in Middle Earth.
Taking the boats, horrible, and evil though it was, was a genuine means to an end.
This is simply banal politics that not only split the Noldor at a time they really, really needed it, but probably cost hundreds of thousands of them their lives during the crossing of the Helcaraxë.
Once you give in to justifying evil for a cause, you will innevitably become more than willing to excuse other evil for it.
But you know what the best part is?
Acording to one version of the Kinslaying, One of Feanor's sons wanted to go back to Valinor, presumably to repent, and despite having sworn an "unbreakable oath", he was willing to go back on it because he came to realise that his actions were wrong.
And he was not killed by some divine bolt of lightning, but his own father lighting the ship he was on ablaze withouth knowing he was there.
Again, Tolkien makes his view on people who cling to "justifications" for evil quite clear.
The second Kinslaying is even worse than thw first, for it exposes absolutely everything for how it is.
It is important that this takes place AFTER the battle of unnumbered tears.
There is no glory left for the sons of Feanor at this point, for any chance of actually defeating Morgoth, avenging their grandfatger, father and all their now fallen brothers and reclaiming the silmarills by some glorious feat of arms has now passed.
They, and all the rest of beleriand now lives in the shadow of Morgoths innevitable victory, which he is taking his sweet time with.
But since there is small chance at taking the silmarills from Morgoth, they give up on that, because that is the hard road, and these men do not have the character of strength to actually take the hard road, which demands actual strength of character.
Instead they decide to target the one they can target, the one carried by King Dior, a man who has done them no harm, no injustice and by all accounts is a good man.
And they murder him. They kill his wife, and destroy his kingdom, one of the few realms that still exists and still fights the good fight against their supposed final enemy Morgoth.
And then, in an act of cruel and wicked spite, angry that this man had the gal to resist when they came to steal from him, and murdered his people, they take his two sons out in the woods, and leave them to starve or be slaughtered by wild animals.
But should we expect better? These men partook in all the ills of the first kinslaying, and so, are willing to cross any and all lines for their "great cause", for that is all that they have left.
Maedhros tries some repentence at this point, and decide to seek out the children his men left so cruelly to die, but he does not find them. The narratice does not reward him for this halfhearted attempt at redeeming himself if he is not willing to give up this vainglorious oath of his.
Which leads us to the final kinslaying, though i would argue there was a fourth one, which serves as the ending of this tale
The third kinslaying is the worst of all, and it is such an evil act that even some of their own troops, people who stood by them through the first kinslaying, the betraying with the burning ships, the tragedic defeat and aftermath of the battle of the unnumbered tears, and the second kinslaying, turns on them and tries to oppose them, having found the guts to do what none of the sons of feanor ever had and abandon this foolish quest.
Upon learning that Elwing, the only surviving member of Dior's family they unjustly slew is chilling with the survivors of the rest of the genocides of Beleriand, they decide, screw it, lets just sack this last remaining, undefended city, kill everyone we can, take the silmarill and sort out the consequnses later.
The previous kinslayings were unjust, evil, wicked, but they were military conflicts. There was a fight, regardless of how onesided they might have been.
The slaughter at the havens is anything but.
Is is genocide, snuffing out, or as good as, the last remaining survivors of Doriath, Gondolin and others.
If any of them survived this final sack, they were so few that their entire cultures effectively died out with them.
And once again, they are denied their price. They capture Elwings sons, Elros and Elrond to use as hostages in hope of negotiating back the silmarills.
With all of this in mind, the final chapter of this story is not particularily surprising.
For after the war of wrath is over, and the Valar's forces has done what they could not, and defeated Morgoth and taken back the silmarills, they are bluntly denied them when they try to claim them from the victorious forces, citing all their very evil deeds.
The two surviving brothers have a debate of what to do. Breaking their oath, or trying to fulfill it, either by once more trying to take them by force, or by going back to valinor and seeking pardon, hoping to once more get back the silmarills not by force of arms, but by showing themselves worthy of them after seeking redemption.
Of course, the first and last option would require actual strength of character, and so the two of them decide to take the two silmarills at hand by force, assuming they will die trying.
However, they are denied that death, and instead the commander, after they slay several of his men, decides to let them go with the silmarils, rather than respond with the death these two probably deserve at this point.
Their prize, as he expected, rejecta both of them.
The holy jewels they started this whole adventure to find, the ones they exterminated people to get, now violently rejects them for their evil deeds and character.
And in one, final set of utter and total showcase of what pathetic men they are, rather than abandoning the gems so that they could be returned to Valinor, they instead ensure that if they cant have them, nobody can.
Maedhras throws himself into a gaping, fiery chasm to ensure that both he and the Silmaril are lost beneath the earth.
Meanwhile Maglor throws his into the sea, to ensure the same thing, only chooses not to take his own life as well.
It is a last, spiteful set of acts that shows that neither of these men ever had the fortitude to do the right thing, and as a consequnce of their horrible oath, it all spiralled to this point, where even if told by the silmarills themselves how evil they have become, they still arent able or willing to do the right thing if it means going against their own oaths.
Because if they did, then that means that absolutely every, single evil, monstrous thing they and their brothers did was conpletely inexcusable, and they dont have the guts to do that.
It takes character to admit that you were wrong, owe up to your mistakes and take responsibility rather than clinging to the justification that brought you down this road to begin with. Or as Tolkien described both himself, his countrymen, and his enemies, all so similar to each other during the first world war.
"We were all Orcs in the great war" - J.R.R Tolkien.