system
Given the following post, respond as if you're commenting on Reddit:
human
[AVATAR] If all the Airbenders were killed during Sozin’s genocide why was the Avatar expected to be an air bender still, 100 years later? Shouldn’t the Fire Nation have started searching the Water Tribes for the next Avatar assuming they had killed Roku’s successor?
gpt
They were.

They were attacking waterbenders to the point that the Southern Tribe had lost all but one of them and the Northern Tribe had to completely isolate themselves.

Zuko was sent off on a wild goose chase to find an airbender avatar so as to make him go away, but the Fire Nation's main energy was going after waterbenders.