Because everyone has a different opinion on what is "an exploit", "lame" or whatever - look at the guy who claims the gear trick was an exploit* - the discussion is rather meaningless.
*Noone got punished for that one, hell, everyone who DIDNT do it was considered a bad pve player - that doesnt foster the impression that exploits are bad, or that the judging authority is something but a joke.
There is either "within the clearly written rules" or "against the clearly written rules".
If there is a dispute, there are 2 ways to handle it:
1. it is valid until an opportunity arises to change / clarify the rules (next match, more often next "season"), or
2. judgement call.
In the later case, the judge is part of the game, and "play the judge" (by misleading him and manipulating him into thinking that your way is the right way) is - sadly - part of the game. Guess which option i prefer?
The general mindset behind the "exploits are bad" people is what i would call scrub mentality:
people who dont play the game "the right way" (not necessarily the way the devs intended the game to be - since everyone has his own opinions on valid gameplay, remember?) are somehow bad - unless they play less successfully, in which case they are "creative"
In Guildwars this means: everything that the client allows you to do is legit until it stops allowing you to do it.
Everything else is theological guessing. Did the "creator" really intended the AI to be so stupid? Am i really a bad person for using spiteful spirit in pve? When those doors should be solid, why did i just manage to get past them? Am i really bad when i only see ugly 2d sprites even though the devs "really really promised" to have state-of-the-art 3d engine for Guild Wars 2?
The last example should hopefully show: when reality and "intent" differ, it is always the fault of the creators. Nothing prevents them from fixing the problem - see all the patches that closed "lame" ways to play Guild wars. But until then, every "exploit" is part of the - competitive - game, and everyone who doesnt find or abuse it has only himself to blame. Of course, you could get banned for that - so you have to play the judge a bit ... lame, but whatever.
personal note: i consider fairplay (in a game, not life) to play to your fullest potential, and disregard all subjective traces of mercy and guilt. Its not about killing kittens, its about playing games. Its no fun when your opponent doesnt do something that would have increased his chance of winning, and even worse when he claims that he is somehow doing me a favor. If the game turns out to be degenerative (ex: if you play a mesmer you win, if everyone selects a mesmer the winner is randomly selected), its time to find another game.