I have theory that I apply when I am driving, anyone who is using their own power to travel deserves the right to be given way too, it costs me zero energy to appy a brake and the move on, pity every motorist does not apply the same.
The bridge in that clip is a nightmare, and as proven by Gaz's cam, it doesn't matter how strong your primary is you will still get some twunt try and push by. Not only is it a short sharp up hill it is double white lines and thin, no way could you safely get a car in each direction + bike, it is used by several bus routes and a blind brow of the hill, only and I mean only a plonker would try and overtake a bike there.