I guess I left out a key phrase, within the limitations of the law. You will have to excuse me for not expecting people to take the example so literal. I kind of figured the example would be the true source of understanding of my comment.
Also, try and consider the view of an outsider. If you saw some random woman kick a man in the nuts, most men would instantly sympathize with him because we know it hurts. Its not until we realize that she is merely helping herself that there was a purpose to kicking the man in the nuts.
Similarly, guilds who may kill a zone that people claim is below them can be doing it for several reasons. Lets continue using our storm's eye example. Outside of the loot, which is pretty nice as Aisling said, there are also the quest gems. These quest gems are a needed step towards the combine armor, which is friggin sweet. On top of that, there are relic chances from each of the named mobs iirc. So, even if I have all of the loot that I can use from Storm's Eye, I may still need to go back for quest gems. If I am already in the zone for quest gems, I might as well kill the named for chances at relics or gear upgrades for guildies who may need it or even alts.
Essentially what I am saying is that each of these zones exists for more than loot in the sense that we normally think of it. Many of them, namely the planes, also have side quests that members of high end guilds will need to farm in order to complete. Essentially, the "farming" of lower tier zones is not meant to be a kick in the nuts, it is merely higher guilds doing what they can to continue to progress.
