anyone who would write a full essay on that topic must have gotten into philosophy for the wrong reasons.But must someone who knows the secondary literature on Heidegger inside out have gone into philosophy for the wrong reasons? As I recall, Harman himself has read every word of Heidegger's work in German. Perhaps reading all the secondary literature would be impossible, but is there another reason why it would be a bad idea? It might be symptomatic of obsession or pedantry, but it could also be the result of humility and seriousness. Those seem like good qualities to me.
Let me expand that point: anyone who even knows off the top of their head where to find such an essay must have gotten into philosophy for the wrong reasons.
I have nothing against wanting to change the world, but science and politics seem like better avenues for that than philosophy. The point of philosophy (as I see it) is not to change the world but to understand it. And not to understand it in the kind of way that Kierkegaard made fun of Hegel for (I wish I had a quotation to support this implication) but to see it clearly. In other words, work in philosophy ought really to be a working on oneself. Or so it seems to me.