Unwritten transit conventions require riders to stand on the right to allow others to walk on the left. The overtaker who has the better view bears primary responsibility to avoid colliding with the overtaken. There is a correct side for passing, and both parties share a duty to prevent collisions. The overtaken must hold their course and avoid surprising movements that complicate overtaking. Deliberately blocking passage, such as grabbing a handrail to force a passer to the wrong side, increases collision risk and is a serious infraction. The overtaker should pass on the correct side and slow down when necessary.
Although your question pertains to walking, every type of vehicle has its own etiquette for passing, and examining the common features among the different systems is instructive. You remembered two of the rules: 1. that the overtaker who has the better view has the primary responsibility to avoid colliding with the overtaken; and 2. that there is a correct side for passing someone. Unfortunately, you forgot the equally, if not more, important shared duty to avoid a collision.
The rules of sailing express this gracefully by requiring the overtaken to hold their course in other words, not to do something surprising that makes it harder for the overtaker to prevent a collision. Grabbing the handrail only to prevent the 20-something from passing on the wrong side made a collision more likely, and was therefore the worse infraction. He, of course, should have passed on the correct side, and also slowed down.
Collection
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