This is such a terrible story that one has to ask what is the purpose of keeping its memory alive. And from all places, nowhere else but in Israel’s formative literature: the TaNaKh.
There are two possible answers to this question:

Measure for Measure
Pessah is more than only the Jewish people’s longing to be free to serve the world by finding treatments for diseases, water for drought-stricken areas, and so on. Pessah is also meant to bring to the forefront of Jewish consciousness the belief that human actions have consequences.