Legend of Korra Season 2: Discussion thread. Spoilers ahead.

[darkknightkryta]

WIzarDE said:

Well they have edited it with the new info provided in the latest episodes.

"During the era of Raava, the power of waterbending was first granted by the water lion turtle, who would temporarily provide it to those venturing into the Spirit Wilds. However, after the lion turtles renounced their roles as protectors of mankind during the era of the Avatar, the turtles refused to give people bending anymore. The descendants of the water lion turtle eventually learned to waterbend again by observing how the moon pushed and pulled the tides of the ocean; they learned how to simulate the effect themselves.^[2] As such, they have a strong spiritual connection to the Moon and its counterpart, the Ocean. In fact, waterbending is the only bending art to originate from spirits instead of animals, and any adverse effect on these spirits detrimentally affects waterbenders too."

That's still not right cause they show the lion turtles unlocking bending in people after the fact...