Dogs and humans don’t understand that tortoises and turtles can be very assertive and are not the least bit afraid of any dog, no matter how big the dog might be.
My box turtles used to frustrate our family dog by eating his dog-food off his plate and drinking the water in his dish. He barked, he yapped, he made threatening gestures… but what good were those? He was dealing with box turtles, and they knew he couldn’t hurt them.
I once caught a dinner plate sized snapping turtle, near a lake in the Midwest. It didn’t withdraw into his shell, not even for a moment. Instead, it strained its neck, trying to bite my hands. After I showed it to friends and family, I returned it to the lake where I had captured it and it swam away at an impressive speed. About 20’ away from me, it stopped, looked back, and gave me the dirtiest look I’ve ever gotten, then swam further away, rapidly. That was one tough creature.
The turtles in the video were not about to take any nonsense off of a dog.
Snappers have a bad reputation, but it doesn’t take much effort to tame them.