system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] Why didn't the Eternals try to stop Ego when he visited earth?
gpt
To break from the other "they didn't know" answers:

The Eternals are not authorized to intervene in non-Deviant threats. Ego is not a Deviant, and his actions do not involve Deviants. 

Regardless of if the Eternals are aware of/monitoring Ego, they don't have command authorization to do anything about him.