Exactly. 70 in a 60 isn't enough for some people, they want to do 80, and expect others to clear a path for them. Screw those assholes.
Doesn't matter what speed they are going - you are not the police, you do not have the right to enforce the law as a vigilante.
Move over, as is the right thing to do, and let them do their thing and perhaps get busted down the road.
Nobody should ever be cruising in the left lane. States have variable laws on the books for this, some are more lenient and basically just say clear the lane for those wishes to pass, as you must pass on the left. Other states, thankfully, are also starting to slowly enforce the "stay as far right as you can unless passing." So in a three lane highway (one direction), you are in the far right lane unless passing, and the only time one should be in the far left lane is when passing someone who is passing someone, essentially. It still works out that you may be in the left or middle or awhile because of a lot of traffic, but that's how it is supposed to work, and once you have clearance, you then shift back to lanes to the right until you are in the far right lane or there is more traffic.
You shouldn't ever require someone to pass you on the right, it creates too much risk for both parties when there is traffic. But people just like to cruise in the left lane and never move over.
I won't tailgate hard, but I'll get relatively close and slow down a little, giving them time to move right. But I won't slow down forever just to prove the point, not anymore, so if I don't see indication they are changing lanes, I make the pass on the right. I hate doing this, hate it, hate it something terrible, but I don't have a choice when assholes don't free up the left lane.
What I hear most often, usually sums up as: "I'm going above the speed limit as it is! How dare they get upset that I won't let them pass!"
As for the video, the tailgater is definitely at fault and that's the risk they take by doing that. Doesn't matter the situation on the road, you legally must always retain a safe distance between vehicles so as to react to absolutely anything possible. If you can't stop in time, you are following at an unsafe distance, and are 99.9% of the time held liable.
But the brake-checker should have a few citations as well: brake-checking is wholly unsafe for both parties, so some citation must exist for that; and failure to yield the left lane should be a ticketed offense. In some states it is, but even in those it is rarely enforced.
I think Michigan is starting to crackdown on it, and I wish more states, like Ohio, would change the code to be more strict and then act on it.