It often feels to me that HN's view of Buddhism is "whatever bits of philosophy I happen to agree with". It's true that throughout history, there have been enough different expressions of Buddhism, practiced by at least a few people, that it's possible to say a lot of things 'are Buddhism', but it feels dishonest to me to rely on that in comparative analysis with a much more doctrinally stable religion. The difference is not fundamentally one of belief but of legibility of belief: with Buddhism you can get away with almost anything (did you know that most all modern Buddhists in Japan believe in the pure land -- for all intents and purposes heaven?), but with Catholicism there is but one creed.