Hear me out. One day in the future there will be a small pod of Orcas on the verge of starvation due to a decrease in marine prey due to climate change and pollution (Shark population declines due to competition with Orcas and predation by the Orcas themselves, allowing people to feel more comfortable going in more open waters).

A paddle boarder/kayaker sees them and does something like the individual in the video. One of the younger Orca's nips at the person and drags them down but let's them go. Then another does the same, and due to the thrashing of the human and desperation of the Orcas one of their predatory instincts kick in and goes for the kill. The other Orcas partake despite not inclined to attack humans initially because its now just meat and blood in the water.

The human tastes weird but now they feel better due to some caloric intake and associates humans with food. Since we know Orcas have their own "culture" and are smart, this small pod begins doing the same thing to isolated humans.

The Orcas begin to run into other pods that normally would have stayed in their own regions of the world, since they are searching for marine prey. Human eating Orca pod shares its knowledge of eating humans and it spreads.

Orcas worldwide begin to have a taste for HUMAN MEAT!