Why couldn't Jade just wait until the Returning Sword Sect was destroyed?

It was because she truly despised its members.

In comparison to the Rakshasa Temple, the Returning Sword Sect was the most humiliating and hurtful to her and the Flying Eagles—the Returning Sword Sect was the first of the six ancient sects, and the Flying Eagles were the first to face them.

The origins of this sect were unknown at the time.

When Flying Eagle's people arrived at the door, the two sides opened it to