Varför kränkte Morgoth Hurin istället för att döda honom?

Det var nog en kombination av två faktorer:

• Grym hämnd Som DVK påpekade i en kommentar till frågan var Húrins öde en extremt grym tortyr; Morgoth satte en förbannelse på Húrins hela familj och tvingade honom att se det spela ut (betona min):

  Therefore Húrin was brought before Morgoth, for Morgoth knew that he had the friendship of the King of Gondolin; but Húrin defied him, and mocked him. Then Morgoth cursed Húrin and Morwen and their offspring, and set a doom upon them of darkness and sorrow; and taking Húrin from prison he set him in a chair of stone upon a high place of Thangorodrim. There he was bound by the power of Morgoth, and Morgoth standing beside him cursed him again; and he said: 'Sit now there; and look out upon the lands where evil and despair shall come upon those whom thou lovest. Thou hast dared to mock me, and to question the power of Melkor, Master of the fates of Arda. Therefore with my eyes thou shalt see, and with my ears thou shalt hear; and never shalt thou move from this place until all is fulfilled unto its bitter end.'

  The Silmarillion III Quenta Silmarillion Chapter 20: "Of the Fifth Battle: Nirnaeth Arnoediad"

  Húrin måste titta på historien om Túrin Turambar, en av de mest gut-punchingly skrämmande tragedierna i The Silmarillion , spela ut. Och många av huvudaktörerna är hans vänner och släktingar.

• Han vill fortfarande hitta Gondolin. Det verkar rimligt att Morgoth antar att Húrin skulle vilja återvända till Gondolin efter denna långa tortyr, och han satte spioner på Húrin med detta ändamål i åtanke ):

  Thus his freedom did but increase the bitterness of Húrin's heart; and he departed from the land of Hithlum and went up into the mountains. Thence he descried far off. amid the clouds the peaks of the Crissaegrim, and he remembered Turgon; and he desired to come again to the hidden realm of Gondolin. He went down therefore from Ered Wethrin, and he knew not that the creatures of Morgoth watched all his steps

  [...]

  For Húrin stood in despair before the silent cliffs of the Echoriath, and the westering sun, piercing the clouds, stained his white hair with red. Then he cried aloud in the wilderness, heedless of any ears, and he cursed the pitiless land; and standing at last upon a high rock he looked towards Gondolin and called in a great voice: 'Turgon, Turgon, remember the Fen of Serech! O Turgon, will you not hear in your hidden halls?' But there was no sound save the wind in the dry grasses. 'Even so they hissed in Serech at the sunset,' he said; and as he spoke the sun went behind the Mountains of Shadow, and a darkness fell about him, and the wind ceased, and there was silence in the waste.

  Yet there were ears that heard the words that Húrin spoke, and report of all came soon to the Dark Throne in the north; and Morgoth smiled, for he knew now clearly in what region Turgon dwelt, though because of the eagles no spy of his could yet come within sight of the land behind the Encircling Mountains. This was the first evil that the freedom of Húrin achieved.

  The Silmarillion III Quenta Silmarillion Chapter 22: "Of the Ruin of Doriath"

Húrins frihet orsakar också en annan ödmjukhet, som att döda Thingol, vilket i sin tur leder till att Doriath faller och att Elves och Dwarverna söndras, men det är inte klart huruvida Morgoth visste att dessa saker skulle hända. Det är säkert möjligt, i vilket fall det ger ännu ett motiv, men vi kan inte vara säkra.