I never dove with that species, but when sharks dart around, have pecs down etc. they are excited and it is a LOT more risky.
Perhaps repeatedly allowing them to get too close is providing a setting that promotes their further excitement? Is this what people want? Do the divers want the sharks to approach super close, so they could reach out and touch them? Is that the behavior that is desired? If so, then continuing to have everyone unarmed with zero deterrence and absolutely no defense from an escalation and attack is an understandable management technique.
If, on the other hand, the goal was to ensure the sharks do not commonly invade personal space (and be subject to the escalation of excitement that it may evoke), then a few DMs could carry a pole spear or sharp stick and jab them hard when they get too close. Even chasing and feigning aggressiveness, seems to cause a lot of sharks to back off and be respectful - assuming there are not strong offsetting factors like a struggling fish or an obvious stimulus like scent, sight, struggling sounds of prey, witnessing other sharks feeding or approaching prey items aggressively with zero consequences etc. Managing sharks seems like it involves not letting their behavior in a particular interaction to spiral out of control. Keeping things mellow and respectful and calm is preferable to trying to jab 3-4 sharks that are totally amped up and having everyone "run" for the exit.
Perhaps there are not a huge number of sharks that the divers are commonly interacting with and several of the individual sharks have, over time, taken on dangerous and aggressive behaviors? These individuals may have "a bad attitude" and if they persist, other sharks may learn by emulation and also be emboldened - perhaps that is at play here?
I don't think sharks are stupid, are unobservant, are unaware of hierarchical positions in a feeding or aggregating situation or are incapable of learning. They can learn the lesson that is being taught if it is not too complex and if it relates to their natural instincts.
Although I am NOT a fan of this activity at all, just look at a well run shark feeding operation. The experienced feeders are very much aware of the over all excitement level of the sharks. The food is doled out slowly and in a very controlled manner and if a few individuals seem to be getting too aggressive or competitive, then the feeding is suspended until everyone calms down. Don't think I am anthropomorphizing the situation one bit. In my opinion this type of activity is unwise, unsafe and has the potential for negative consequences for the individual shark's safety, but on the other hand, the safety record is not as bad as it could be and it clearly demonstrates the ability of humans to influence, if not modulate, the behavior and intensity of activity for several large and dangerous shark species.
Perhaps removing several or a few dozen of the excessively aggressive individuals along with the guides carrying shark deterring sticks and a policy to ensure that these (man eating) sharks are not allowed to get too close to customers before they get a poke, might be an economically superior solution compared to shutting down the diving for an extended period of time? Selective elimination of aggressive individuals is not too complex and spearfisherman in other areas of the world have done so on occasion.
In Florida, the destruction of a large aggressive alligator is widely accepted and seems to be beneficial to the populations of alligators that live in relatively close proximity to humans.
Then again, if the desire is too promote or allow the sharks to approach people within 1 foot and make "test" runs of aggressive passes with impunity, then maybe this isn't an option. Perhaps an occasional calf or forearm is a necessary sacrifice for the benefit of being able to get a close up of a shark's eyeball.
