It's all about target of oppertunity. I also know that I've saved many groups by taking out the enemies healers/casters during their 'fair fights'.
Yesterday I attacked what I thought was a lonly paladin, stupid as I was I forgot about the enemy adds. I got jumped by 4-5 albs.. did I get upset? Yes, but what does it prove? That we're not the only realm who get these 'adds' so I really dont understand why you think our realm should play more 'fair' if the other realms don't. Fair as your fight might have been you can never be sure when enemy adds more to the battle so imo take em out fast using all you got (including people's help who are NOT in your group)
Dunno if this makes sense since I woke up 1 min ago and im so tired I cant see the screen fully

Edit: btw, I remember having a discussion about this pre-nf too...then it all went quiet. tbh I thought the ones complaining had grown up

/Ankh