> Emacs fires "user-error: Abort" after pressing "q" to abort org-capture.

This is intended. Normally, it just shows up as a message in the
minibuffer. Or do you have debug-on-error enabled?

Same as Ihor, when I press `q` in the org-capture screen I only see "Abort" in the minibuffer. Where do you see the `user-error`?  As long as the effect is what you need (getting out of the capture screen), what is the problem with the code using the `user-error` function to achieve this effect?