Why is the pigeon so big?

Ultimately leaves behind, not an answer, but a state:
Understanding has already happened, but language does not stop.
The question no longer points toward the unknown, but becomes a behavior that is continuously maintained.
Here, there is a mismatch in levels of communication: you are explaining the cause, while the other person may still be operating at a basic “is it or is it not” level. This misalignment prevents the explanation from moving forward and instead keeps pulling the conversation back to its starting point.

At the same time, there may also be a mild resistance-to-change mechanism: when an answer has the potential to disrupt an existing belief or cognitive structure, repeated questioning becomes a way of delaying acceptance.

In this sense, in an environment where everything can be explained, not ending the explanation itself becomes a form of expression.