>The fact elephants have 4 forward facing knees also prevents a gallop.

That's inaccurate. Elephants have knees and elbows that bend the same direction as any other mammal's.

This skeletal diagram is an easy illustration - https://imgur.com/HtrRcOb

And here you can see the elbow joint vs knees on a living elephant - this elephant has its elbows bent backwards as normal, and its wrists pressed against the ground as it's 'kneeling' to dig.

That "fat labrador bounding" (pretty accurate description lol) is unfortunately not a natural motion but is caused by this elephant's front legs being hobbled together by chains. Example pic of chain hobbles on another elephant.

In OPs vid, you can hear the chains rattle and see them connecting the front legs together as the animal moves. Trying to run while hobbled is what's causing the unnatural 'bounding' gait pattern of this elephant.

In OP's video example, that elephant's front legs are hobbled - that's when you rope or chain together (as in this case) a pair of legs to restrict an animal's natural range of motion, movement ability, and speed.

You can hear the chains rattle as the elephant moves, as well as see the hobbles, especially when the animal is close to the camera, like around 25 seconds into the video. The hobbles are causing this elephant to have an unusual gait.