[db48x]

The individual controller won’t know exactly how many airplanes are ahead of this one, and even if they did they can only estimate the delay. In this case the estimate they gave the plane turned out to be optimistic, because the planes ahead of them were taking longer to land than expected. Certainly saying “This conversation is over” would be rude in most circumstances, but it merely reflects the reality that a controller can only spend so much time talking to each crew. The crew already had all the information the controller could give them, and simply needed to make a decision rather than ask more questions.