Marlow's conflicted attitude toward the Africans. In what way is he condescending? In what way is he respectful? How can you reconcile this polarization?

http://www.gradesaver.com/heart-of-darkness/q-and-a/what-is-marlows-attitude-toward-the-african-people-he-encounters-on-his-trip-up-the-congo-87417/

In addition to the above, I don't really see him as condescending. He comes to the Congo and is suitably shocked by the depravity he sees. Marlow is critical of his own European culture while remaining pretty objective about the hell hole his countrymen have turned the Congo into.