Judah wrote:

Because the proper response to "was that for N12345" is from the
controller, and is either "no" or a repeat of the call.

Since the call is going to be repeated regardless, the obvious point
here is to simply not say anything and await the repeat. Saying "was
that for blah, blah" just uselessly clutters the frequency even more.

I recall one time while in NY airspace when the controller was
constantly being stepped on, but apparently didn't realize it. After
about the third or fourth repeat, he suddenly berated his listeners by
stating, "I need all of you pilots to pay attention to my calls and not
make me repeat everything twice!"

We all were listening and ready to react, but all we heard were squeals.

--
Peter