Is it more arrogant to ruin someones else's day for fun or to think that the world must always go your way, all the time and complain when it doesn't? Sure griefers are jerks, but the people who freak out when something doesn't go their way, are worse imo. It's a Video game, sometimes you win, sometimes you lose, sometimes you get killed, sometimes you do the killing. As a pirate, i've been called names that would make a sailor flustered. I've even learned new combination of curse words from the people, who can't take it when a game doesn't go their way.
Killing, stealing, trading, exploring, mining, hunting, all of these are completely valid in game and supported by the devs, but people only have a problem with the first two, they seem to think because it negatively effects others it's griefing. They are not, griefing is negatively effecting others in a way not supported by the gamemakers, such as team killing or killing people in stations(which is why this was fixed). Since murder and piracy was confirmed valid by the devs, they are not, and can never be griefing.