This is indeed a problem when you by fiat declare certain systems off-limits as your form of protection for new players. It is completely plausible that a veteran player doesn’t know the list (which even has changed recently) and explodes a true new player thus inadvertently breaking the rule. Some sort of clear safe space apart from the sandbox for the NPE would be a cleaner solution.
Still, these are outliers - 99.9%+ of new players are not killed in a rookie system, if they are even killed at all. Anyone who systematically shoots new players will be called out in short order and punished and all the rumblings point to CCP being very liberal with replacing new player’s ships, even when they are lost “legally”. And even then, there is CCP Rise’s presentation which suggests that being exploded when new might be good for new player retention and calls into question the rationale behind this rule in the first place:
I get the instinct to want to protect newer players, but they aren’t dying in significant numbers to other players in highsec as your data shows, even if it isn’t a non-zero number. And if this really is a problem somehow, the solution needs to be one that can be targeted only to true new players, and not involve just handing out more safety that will be exploited by risk-averse veterans as our friend there proposed.