@Turkeysocks Telling the spirits not to help humans will not work as most humans cannot see /sense them in the first place.
To humans of this world spirits are seen as just some legend. That was why Ruri was kicked out of the human palace in the first place. They did not know she was a cherished one.
In the first few chapters, as the spirits were angry that Ruri got kicked out of the country, they crippled the human country’s ability to grow crops. But that also did not stop the human royalties from forcefully taking the remaining crops and recruiting soldiers. Even the priests, who has some ability to sense spirits, were using the chance to fill their pockets.
TLDR
Spirits can’t stop the war unless they straight up destroy the human country