system
Given the following post, respond as if you're commenting on Reddit:
human
[ATLA] Regarding the airbender genocide

So the Southern Air Temple was Aang's home and also monk Gyatzo's. The fire nation came in and killed everyone including Gyatzo. 

My question is this. Why did they leave the bodies of their fallen? Roughly twenty firebenders were used to take down Gyatzo but in end there were no aorbemders left to resist them. Why would the firebenders leave so quickly as to not collect their dead?
gpt
Either they were superstitious, in a hurry, or it was too expensive to remove them.

The fire nation is surprisingly tradition bound, and it's possible that they thought the spirituality of the air nomads would allow then to return in spirit form.  
It could also be they were nervous from all the killing, as even though the fire nation is known for their calculating brutality, they're still human.

They might have also been in a hurry to kill the rest of the airbenders, since breaking the incarnation cycle to end the avatar was the main goal.

Not to mention, the way to the Air Temples are treacherous without airbending, and the fire nation was still a hundred years away from readily available flight capabilities, making removing the bodies far more costly than leaving them to rot.