Maybe I need to go back and watch some of those episodes again, but what evidence is there that the ship or meteor's crash was what caused the extinction level event other than people were told it was?
The people were told it was an asteroid impact, and that the spaceship technology for the colonization program was a homegrown human invention. Over the course of the season, we got hints that gradually revealed that the "asteroid" was actually a spaceship and that the Resolute's space drive was secretly salvaged alien tech. Strictly speaking, that full backstory hasn't even been revealed to the main characters yet; it's something we've been able to piece together from the clues we've been given, but much of it is still a mystery. So the alien ship crash already is the secret explanation behind the official story of the cataclysm.