[racket] Why does rackunit show the stack trace of check failures?

I'm trying to clean up the output of some test cases so they are
easier to debug when the go wrong. One of the issues is that the
rackunit text ui always wants to print the stack trace of check
failures. I never find these useful since they just show frames of the
test code, not the code under test.

The code is here:
https://github.com/plt/racket/blob/master/pkgs/rackunit-pkgs/rackunit-lib/rackunit/text-ui.rkt#L105
Added here:
https://github.com/plt/racket/commit/f6b73f01e174337534ed11e7ff78d095f16d6088

It is guarded by a (when #t ...), could we change it so that is
instead a (when verbose? ...)? verbose? is already affecting other
parts of the output in this function.