Right, but here lies the difference. In most MMOs (WoW) for example, if you want a particular piece of armor you have to go to run a specific dungeon, and maybe even specific boss over and over and over again.
That's not true with guild wars. Karma is obtained through WvW, dynamic events, your personal story etc. You have several options available that just naturally will accrue karma through regular play. You don't have to deviate from what you want to do to get that piece of armor. Ya, you may get it faster if you find the quickest event out there, and run it over and over and over again.. but that's on your head to do. The game isn't forcing you to. THATS a grind, repeating the same action over and over to a goal. You are not forced to do this in GW.