I understand your point of view entirely, but it all boils down to what the game can support. It is just as "unrealistic" to allow the same "criminals" to commit acts of mayhem time and time again before a "realistic" society inflicts permanent outlawry or terminates the criminal.
I don't think any of the "hardcore" players would agree that permadeath for being a "three time loser", or the equivalent, would be a good idea. That would be "hardcore", though.
If the penalties for such things would at least far outweigh the economic benefits, that would lessen the acts by those that can do maths.
It wouldn't limit the antisocial griefers, though. The "I live on the tears of others" nonsense attitude, in other words, the "I want to ruin your enjoyment of the game" attitude, is an out-of-game, player-rather-than-character, affliction. It requires out-of-game, mechanical solutions, not simply "find a bigger gang to hunt him down".
These games are games-- they are intended to be entertainment, in return for one's entertainment time and money. If one's entertainment is founded upon ruining others' entertainment, then that is an inherent negative that the person brings to the game.
If one wishes to get into combat with other players, there are ample opportunities for one to do that. Granted, they may know that the possibility exists and be better equipped to deal with it. That seems fair to me.
If one just wants to take a couple of hours and play the game, there are opportunities to do that, too. It would be nice to keep it that way.
Now: a common response from the other "sandbox" game usually devolves into name-calling, "WoW is that way", and a lot of other immature nonsense The logical end of that would be a tiny, niche game with griefers having no one but each other to grief. If that is what we wish this game to become, then it can be made so.
Alternatively, eliminate safety altogether; make the game full-bore PvP from the get-go, advertise it as such, and see how many players you get to sign up. My guess: not many. In an EP-accumulation game, the experienced players could annihilate anyone new so easily that new folk would have only two choices-- join a bigger gang, or leave.
I have been playing these things longer than some of the players here have been alive. I have also been involved with game design. The Devs and marketing simply have to decide what the demographics of their audience is to be. Wide appeal means you cannot simply let people go hog-wild with whatever negative, self-serving play they desire. Niche games, on the other hand, can be constructed towards anything at all.
If players are to be allowed to "do whatever they please", then they must also be willing to bear up with the consequences for doing so. In anything simulating a "real world", the consequences would be draconian.