I see that on my flag list:
Why was it declined?
I can not speak for the person who declined the flag however had it been me i would have declined it to as the question had everything it needs for an acceptable Music Identification Request:
there is really nothing else that could be added.
Now it's possible you submitted the flag before i had edited it however the flag "very low quality" may have still been rejected because it wasn't entirely unsalvageable, as per the flag reason
This question has severe formatting or content problems. This question is unlikely to be salvageable through editing, and might need to be removed.
so the "very low quality" flag is more used when no amount of editing can not save the post