I did watch the video. The Tesla had seven blinks of the turn signal, five of them before entering the lane.

The car in the destination lane was at a safe distance for the Tesla to enter the lane, but it aggressively maintained its slightly faster speed to close the distance to the Tesla until it crashed into the Tesla as the Tesla slowed to a stop. The Tesla did present a difficult situation for the other driver, but only in the sense that the other driver may have felt their ego would be bruised by needing to slow down for safety versus aggressive posturing that they went with instead. Watch the video again. Zoom in. The other driver did have the opportunity to slow down, keep distance, and avoid hitting the Tesla. They did not take that opportunity.

It doesn't matter; cognitive dissonance is in play here. The Tesla cult is activating the standard response protocol to criticism of The Company and Dear Leader.