I agree with you guys that he didn't really hate Lupin enough to not make the Wolfsbane potion for him, plus I think that he is just human enough to not want to make any other students suffer through what nearly happened to him. After all he did put himself in danger to save the trio from being attacked. However on him not hating Lupin that much since he didn't do anything that brings up the question of why he hated Harry so much, since he definitely didn't do anything, I mean he wasn't even there, whereas Lupin was and he should have stood up to the others. But yea I think he also recognises that Lupin is deep down a good person, and he was probably under Dumbledores orders as well.