-facepalm-
Then again, people have enganged in guild wars for lesser reasons. Just like Hessah said, killing GS is a group effort. If one half isn't up for killing it then you sure as heck be a damn good tank in keeping every little baby in check. Not to mention have enough fire power to kill it off before the time runs out.
It's not about the quest kill, it's about succeeding the KQ as a whole. If I saw that there wasn't enough time to kill GS or that we didn't have enough firepower or a good tank I'll run it. And if the other half wants to kill it then they will either have to do with the GS running behind me or be better than me at keeping aggro.
I think your judgement was right. The GW, a waste of everyone's time.