It's a strange situation. If someone writes an essay attacking you, you either have to respond, in which case you're letting someone else pick your topics, or you have to ignore it, in which case people who don't know any better may be convinced by it.
Though I'm not willing to use up an essay to refute someone, I will in a comment thread:
http://news.ycombinator.com/item?id=984217
One thing I still wonder about is whether this guy actually believes what's he's saying, or whether he's deliberately trolling. He seems reasonably smart. How could he not have heard of Franz Hals? On the other hand, who would try to keep a troll going for 4 years?