Its not though there will be hundreds of aircraft doing it every day probably thousands of flights in America every day, never mind the rest of the world. And the last ingestion fatality in Europe was over 5 years ago and I am not even sure that involved the APU being MEL'd.
You have the same issue where ever you park. To me taking a black aircraft reset on stand is not a problem. But other aircraft types it may result in issues.
Airlines repair them fast anyway, not going into detail but its an utter pain in the bum them not working for all involved. We have loads of limitations imposed and other things which would normally not be an issue departing with are now show stoppers. It turns very expensive very quickly and that's without a fatality.
Wait until the final report, its never solely one item or factor. The NTSB you should rightly be proud of, they will get to the bottom of what happened. The APU will feature but there will be a long list of other human factors involved.