This is a dialog I watched on a Netflix show:

Alan: If you had helped me with this, I would've helped you land a job at another airline. One of the big ones!
Bob: Well, Why wouldn't you tell me that when I first came in here!

Question: Why does Bob say "wouldn't" instead of "didn't"?

Question

This is a dialog I watched on a Netflix show:

Alan: If you had helped me with this, I would've helped you land a job at another airline. One of the big ones!
Bob: Well, Why wouldn't you tell me that when I first came in here!

Question: Why does Bob say "wouldn't" instead of "didn't"?

Answer

Both "wouldn't" and "didn't" are fine. "Didn't" is a more direct, possibly less polite way of wording it. It demands or expects a specific answer.  "Wouldn't" is less direct and a less specific answer might be acceptable.

It similar to the difference between "quiero" and "me gustaría" in Spanish.