Are we looking at the same video? The turn signal is on long before, the lane change of the car starts long before.. you don't see any reaction of the following driver even when the Tesla's tires finally cross the line, which is the latest point where the following driver must adapt apeed and distance, but nothing happens?
I am not sure about the US, but in most countries I have driven in, putting a turn signal on is asking for permission to enter another lane, and there is no 'right' to go into the other lane or expect drivers currently there to slow down for you.
If there is an obstruction ahead, the safest scenario is to change to an empty lane ('empty' including safety distance) or brake in your lane to avoid hitting it. If you have some other problem you should probably brake slowly and change lanes to the outer edge of the road whenever there are safe gaps.
I would probably be off the gas or braking based on movement of the car in the other lane as part of driving defensively, though i don't think there is any 'obligation' for me to do so.
The behavior of the Tesla would also strike me as rather odd (assuming a right hand drive country unless there is a off-ramp coming up on the left) as it appears to be pulling over to the wrong side of the road.
