When Madara fought the gokage, he coined the term. Sasuke also let on that he has it too, when he asked Naruto if his feels the same as Madara's during the fight against Juubito. Sasuke is a master of chakra manipulation, I wouldn't be surprised if he really did just choose this size and shape to suit his style. As far as the hate thing goes, Sasuke is doing the same thing as before: Itachi told him he had to kill a friend to attain MS, so Sasuke spared Naruto out of spite. Hashirama told Sasuke the secret that Madara discovered, so Sasuke decides not to re-form his previous bonds. And he's being cold so that no-one will try to change his heart.
