Because of the peculiar nature of this series of posts -- this "bourse" -- I think I am going to intersperse parts with responses to comments, as though it were a classroom. This will enable me to pay attention to the comments as they occur, and also give me a bit more time to write each post.
First, to "formerly a wage slave," the central point here is not the rather familiar notion that the norms of polite behavior are conventional and variable, but that, as Mannheim says, there are certain modes of thought that cannot even be understood without attending to their social and historical context. It is comprehensibility, not truth, that is inseparable. That is a very powerful claim.
My favorite example of cross-cultural misunderstanding [this may be the anthropological version of an urban myth] is the visitor to a foreign country who eats everything on her plate, thinking that that is the polite way to show how good the food is, not realizing that in this new cultural situation, one is expected to leave a little food on the plate to show that one is full. She keeps eating, her hosts keep offering her more. You get the idea. The following is a true story about me. Many years ago, I had dinner at a nice bistro in the Marais in Paris named Les Philosophes [who could resist?]. I ordered filets de hareng marinees [herring in wine sauce], which came in a large handsome cast iron tureen. Not realizing that I was supposed to take a few filets and return the tureen, I stoically ate the whole damned pot! The waiter, to his eternal credit, never said a thing.
Now, to Chris. Yes, that is right. Marx saw this too. The norms of feudal justice and right linger on even after the bourgeois revolution. It takes time for the new socio-economic order to transform the law, politics, art, and philosophy.
By the way, Mannheim's views are very complex. As is my custom, I prefer to expound complex ideas slowly, starting with the simplest cases and building in more and more complexity until the fully developed idea is before us. We are at this point just at the very beginning of a long and fascinating story.