[MLL67RSSS]

Guess I see a different video. If the truck had room to pass on the right they had room to move over to allow him to pass. There are "move-over" laws in several states. The truck passes them and gives a little glance, if his intent was to flip them off he'd have been doing so when he passed them and wouldn't need to slow down to get next to them again. He only flips them off when the slower car that was in front of him suddenly is in a big damn hurry to stay next to him and provoke the situation. Then and only then does he flip them off. Typical left-lane-bandit behavior, have you NEVER encountered one? Both these driver are in the wrong here and luckily no one got killed, this time...

JFTR I've found that if I'm in the left lane and someone is tailgating me, simply moving over and allowing them to pass and go on their way (as required by law in my state) is the best remedy, the farther they are away from me the better.