Being a jerk

[Flamewraith]

There is some lvl 60 ranger named Acrux literally clearing all of the hill giants in the Rathe mountains. He has his epic, and is in planar gear, yet he will attempt to attack any hill giant, even if I or someone else tags it first. Fucking really? When asked why he was being a prick he said "You try finding a group in seb as a ranger." Is this an excuse? Is it okay for him to be doing this?