you'd hope that since almost all the people that play arctic now are adults, that there would be a level of maturity in the way that they behave. unfortunately, this isn't always the case.
experienced players continually become disenchanted with inter-clan politics, their interactions with immortals or maybe just generally get bored of playing arctic and then proceed to act like massive douche bags. they will then random almost any player they come across, repeatedly attacking others even when they have nothing to gain from it except the "fun" of ruining someone else's enjoyment.
these people usually get punished, and it tarnishes their reputation in the eyes of the staff. the people dishing out punishment are going to remember the past behaviour of offenders, and will be less tolerant of them in future. this leads to general whining of "unfairness", yet to use an old cliche, players effectively dig their own graves by their past douche-baggery.
the reality is that staff shouldn't need to develop hard code to shield people from, to quote others, "asshats". the people that still play arctic do so because they enjoy the game. it is a mystery to me why some of those individuals at times would go out of their way to make playing arctic as unenjoyable as possible for others, effectively shortening the remaining lifespan of the mud. furthermore while pkilling is sometimes taken to the extreme it is a fundamental part of arctic. hard coding a protection system would not only detract from that, but it would also inevitably be abused by those same douche bags who it would be designed to hinder.
tldr version : arctic's players are all adults. there should not be a need for hard coded methods to ensure players act in a mature fashion. if you enjoy playing arctic you probably shouldn't intentionally ruin the fun of others who keep it alive, or you may not have a game to play in future.