system
Given the following post, respond as if you're commenting on Reddit:
human
[District 9] Why did none of the Prawns communicate to the humans what they were doing and how they ended up on Earth?

Were they exiles? Did they forget for some reason? 

With the exception of Christopher Johnson none of them seem particularly intelligent. Seems strange they end up marooned on an alien planet in a ship with such advanced technology.
gpt
IIRC the leading theory was that the prawns that survived were from a serf caste. The leaders, the ones who actually controlled the ship, died. There is a good possibility that very few actually knew what they were doing and how they ended up on Earth.