Egos get stood on BS, they dont go very far in this day and age. I think its the Captain's ego that you talk about that needs the re-adjustment. Everything in your first post has a plausible explanation and while there are going to be cocky f/os out there, you cant put everyone in the same category.
Personally, I think that manners, while important, take a back seat to commercial efficiency, that is of course what our companies expect from us. While not forgetting professional courtesy, if the Captain was offended then bid deal, it sounds like it's his problem!
Manners are somthing you use when served your coffee or sandwiches, or given the load sheet. I bet you anything you like that the first officer said something like this:
"Which sectors were you planning on flying today?" to which a reasonable response would be " X,Y & Z or, I dont mind you can choose"
then.....
"I have already ordered xxxxx fuel, it will be here soon, is that suitable?"
to which a reasonable response would be... "Thats fine! or no I think we need more or less, how about xxx"
Professional courtesy and respect should go both ways. BS, you sound like you have been given a very one sided view on this. Any captains out there like to comment.......