He's obviously the bad guy, but has a redemption moment at the end of the story. If you don't get that, you just might be a hackish hollywood film producer.
As someone with Asperger's who kind of wants to be a hackish hollywood film producer, I'll weigh in with my opinion: the grinch is your typical antihero. More bad than good, but we can relate to him, and he's protagonist (central charactor to the story). To go into hackish writer mode, good characters aren't all good or all bad (similar, I would say, to people). That's what makes them interesting. Which side will win out? What caused the bad traits? Will their positive traits be used to solve whatever problem their negative traits get them into? This is what stories are made of, an intriguing narrative.
That and gratuitous sex and violence, of course.
