Alright, though the fact that he lost doesn't seem like a very good reason either. All of the current survivors have lost something dear to them, putting them in the same boat in a sense. Even though he lost, The Witch-King put up a good fight and his defeat was a honorable one on the battlefield, unlike Morgoth who tried to barter from a corner when he most likely knew that such a thing would not work. The Witch-King fought hard and died trying, a rather "successful" death for a warlord such as him.
Besides, on survivor, the hand of Eru does not reach far enough to cast his judgement. Heck, Sauron, the "whipping boy" of Eru (so to speak,) managed to come in second place in the Sil survivor. If a guy who lost a stronghold to a mere two people, was beaten at the height of his strength by a tired king of men(who was rather old, even for his people) and a (rather weak compared to those before him) king of elves, and suffered a "black comedy" ultimate defeat can come in second on survivor, surely the Witch-King can avoid the hand of Eru.
