Their lack of insight into their privilege/advantage was surprising.

Heh, yeah. For the reasons you mentioned (biases, attribution errors, etc), that's not all that surprising to me, and unfortunately I think we all do it. It's most likely something we'll have to train our minds not to do. The only way I can think of to do that is through travel and exposing ourselves to more of how the world lives. Thank you for your comment. Lots of interesting things to consider here.