The birds in the video are out of reach (until one isn't). I'm sure orcas perceive humans in water as very slow and easy to catch - baiting would not make sense.
Or, hmm. Orca are pack animals I believe. If we killed a competing family of Orca (even by accident), maybe the gift is a thanks for the perception of "siding with my family".
They are apex predators, they don’t have natural predators.
Orcas are kind of assholes and it seems other animals care.