You're a strange one, Mr. Grinch. But are you a Jew?
Certainly we at JONJ can empathize with the hatred of Christmas. The incessant music, the insipid movies, the giving of gifts to millions of people who are not us...
But whether or not we embrace the Grinch's evil scheme (or, for that matter, his stomach churning change of heart), does not determine the Grinch's Jewishness.
No, we must look to the Grinch himself, where fortuitously, we find the evidence is slim to none. For instance, he doesn't decry Whoville's celebrations for interrupting Chanukah. Nor does he wear a yarmulke or attend shul. And if being covered in green fur is a stereotype, well, we've certainly never heard of it (let alone seen it, thank G-d).
So, it appears the Grinch is not Jewish. Merely someone who hates Christmas. And that's something that we can all agree upon.