For ‘some reason’ it didn’t make it in to the 24 Sefarim of Tanach that was organized over 200 years earlier by the Anshei Kneses Hagedola.
It is clear that it was trying to imitate the Megilla form. However, being in a time of Tannaim, had it been recorded by the Chachamim it would most probably have been in the form of a Medrash. And it has been. The Medrash does in fact put it in a different order and perspective — in a way that reflects the attitude that The Frog explained. It’s about Gezeiros as an Onesh for laxity, and Mesirus Nefesh that overcame them.
It’s about the freedom to do the Mitzvos properly, and not the freedom to have our own criminals.