Object-Oriented Philosophy explains himself
The point of the “Heidegger is a correlationist critique” is not this: “Heidegger is a Berkeleyan idealist who doesn’t think raindrops exist outside human consciousness.” Rather, the point is this: “Heidegger, like almost all post-Kantian thinkers, sees a difference in ontological kind between human access to the world and the interaction between raindrops and ocean.” Gary claims that this is not true of Heidegger. But there is little sign that he is willing to pay the price this entails. It’s not enough to say “Heidegger knew that raindrop/ocean is the same sort of thing as Dasein/Greek temple, he was just more interested in the latter.” After all, we in 2010 are not restricted to following Heidegger’s personal interests.
I expect there are some people out there who are exclusively interested in whatever Heidegger was interested in (e.g., biographers), but I think there are many more people who find an affinity between what they are interested in and the questions Heidegger asks. Some people of that tendency see Heidegger elaborating what Aristotle understood as the special relationship of humans (as a human this is of special interest to me, more than the rain drops falling in some ocean), and as not exclusively engaged in a post-Kantian debate (as I understand correlationism is), even though Heidegger tried to explain himself to neo-Kantians. As a scientist, I am fairly satisfied with science's explanations for raindrops, but find science's explanation for humans' concerns unsatisfying, or just missing entirely. If I consider science's description of object-object interactions, and then add OOO, I don't see where OOO improves my understanding. It and correlationism sound like metaphysics. But then I've only read one of Harman's books, but on the other hand, having read it, my understanding of the world hasn't changed, so reading more of his books isn't currently on my critical path. But I'm open to being persuaded otherwise.