All because they do not wish to see anyone else suffer the way they do.
Thranduil: -runs up to Thorin and leans in very close to his face-
Thranduil: DO NOT SPEA-
Thorin: Did you just spit in my face
Thranduil: Consider it to be holy water
VillainsNot So Good Guys: Prince Nuada, Hellboy 2: The Golden Army