The manual absolutely is explicit about each WC needing a separate breaker. On page six, it states that, "For sites with multiple Wall Connectors, each Wall Connector must have it's own branch circuit with L1, L2/N and Ground". A branch circuit is defined in the NEC as an electrical circuit after the last protection device (breaker). Therefore, it is quite clear that multiple WCs cannot be wired directly to a single breaker. Perhaps you did not know the meaning of "branch circuit".
The example wiring diagrams are consistent with the branch circuit requirement. Note that, in each case, the wall connectors are hardwired directly to a breaker. There are no diagrams showing multiple WCs connected to a single breaker unless they first pass through their own dedicated breaker.
The statement in the manual regarding leader and followers having different breakers is intended to convey instructions for the case that the WCs are connected to different sized breakers, not separate breakers. This is because the leader cannot know that the followers do not have the same maximum current as the leader so each follower must be commissioned separately to prevent a possible overcurrent situation. The statement does not imply that you can connect multiple WCs to a single breaker. That would violate the explicit statement that the WC must be on its own branch circuit.