Okay, but you left out the rest of that sentence.
> and later for requiring UI changes, including showing a Save As panel for each generated file.
So, Apple found a crash, and instead of completing the review (this assumes they could have, and benefit of the doubt here, they could have), they didn't. They found and issue, flagged it, and sent it back. This means the developer had to do work, resubmit, and then have another issue found. Rather than work through everything, the reviewer found one thing, dinged the app, and moved on.
As a user, that means Apple is delaying apps longer than need be. Sure, fixing the crash is good, but I can't imagine they couldn't have reviewed the other parts of the app and said, "Fix the crash and this other two areas and you are good to go." That would mean a shorter turn around time, and as a user, I get a better product sooner.