is the creature still a sympathetic character at this point?

I think we can say that he is sympathetic.Seeing as everyone hates him for no fair reason, the monster swears revenge on all people, particularly that jerk who created him only to live miserably, ugly, and alone.

Still, he shows his compassion by rescuing a little girl who slips into a stream and almost drowns. He’s a hero, see? The creature has true remorse for what he does. He feels alone and we wonder what he could have been if humanity gave him a chance.