Humpback Whales are protecting other animals from Killer Whales

[Ibrahim]

My hypothesis is that the humpback whales are running a protection racket: you pay them in krill, they beat the crap out of Orcas. Presumably the great white in the video did not pay the protection money, so the humpbacks just stood by while this happened

Seriously though: it's more likely that the orcas--aggressive as they are--are acting in a manner analogous to humans on land: they're insanely destructive, and may be posing a threat to their persons: they likely figure if they help here, then maybe Willie will starve or be weak, and so won't threaten themselves. Or maybe they think (as I do) that Orcas are of the devil, and so need to be stopped as much as possible, because they are of the devil.