]I can understand why Lizzy didn't listen to Caroline, but it puzzles me that she doesn't give credit to Bingley's views. (snip) It reflects poorly on Bingley to have chosen such a friend, so how can Lizzy think so highly of him? I would instead expect her to either look down on Bingley for having Darcy for a close friend, or else consider his opinion more carefully and rethink Wickham.

Remember that Lizzy has some particular factors influencing her opinion of Bingley:

1 - she has noted his similarity in temperment to her sister Jane. Years of experience with Jane have taught her that, even though Jane is highly intelligent, she "is inclined to think to well of people" - she is not discriminating. Lizzy may well feel that Bingley would be the type to excuse rather than accuse of any possible bad behaviour in his friends.

2 - Bingley has already admitted to being highly influenced by Darcy

3 - based on Wickham's accounting, she now believes Darcy to be more than just arrogant, she believes him to be truly a bad person, capable of willfully mistreating a childhood companion. If he is so bad, surely he is capable of lying to Mr. Bingley about the whole affair as well.

So yes, Lizzy is disregarding evidence that is right in front of her, but her reasons for doing so with Bingley's testimony are twofold - she esteems him, but does not count him a good judge of character, and she is convinced that Bingley might be deceived. She is not considering the possibility that she might be.