Short version:
Don't play monsters that don't act like monsters. Don't treat monsters as if they weren't what they are. Doing so is both immersion-breaking and entirely out of character. In particular, if you play an elf or a dwarf, PLAY AN ELF OR A DWARF. These races hate goblins. They kill them. It's part of playing these races. Same thing for gnomes to kobolds (although this is rarely if ever a problem, as I've seen!). Reacting with kindness towards these monsters is, essentially as OOC acts when you should be IC, against the server rules. Please, PLEASE don't do it.
Long version:
ExileStrife
It would be particularly entertaining if your wise or intellectual individual argued the moral foundations SUPPORTING things like monster killing.
Exile, I wasn't sure if you were talking about characters in EfU or people in real life in the EfU situation. I'm going to assume the prior because it makes more sense. By the way, I'm not arguing against you here. Just elaborating on what we agree on, I think, for the sake of the argument! We shouldn't need to argue this as a server/community, but for some reason, it ISN'T accepted. So here goes...
Entertainment value aside, this is just a common and understood facet of LIFE in the world. There is good. There is evil. Monsters are evil. Unlike men, common dwarves, common elves, gnomes, halflings, they are born into evil. They are no different than drow or duergar in this regards. It doesn't require wisdom or intelligence at all to realize that, in the FR setting and particularly in the EfU environment, killing monsters is not only ethically acceptable (regardless of being PC or NPC!), but it is objectively GOOD to do so.
The argument I hear a lot IG is that "you haven't met them all, you can't know that they are all evil." This is absurd. That's like saying, you haven't seen the sky all over the world, you don't know if it's blue there or not! Maybe it's purple over China!
We understand that the sky-color notion is absurd because other people who have been there, seen the Chinese sky, say that it is blue. We don't question them, do we? We accept their AUTHORITY from having been there. The second reason is that, based on our own experience, we know that the sky is blue. There is objective, fact based science that explains why it is so.
How does this tie in to the monster scenario? Based on the AUTHORITY of those who know, we cannot logically deny the notion that all monsters are not evil. It simply can't be done without denying the objective nature of the world (and the good and evil axis) and ignoring what your character should simply KNOW. If you did for some reason refute this, then you might as well refute the existence of the sun and sky in the EfU setting, because even LESS people have had experience with that! Secondly, while good monsters MAY exist, your character has most certainly NOT met any. If they have, well, you've been playing the OC campaign (with Deekin) or reading WAY too much Drizzt Do'Urden books, whatever they're called. To deny that monsters are not all evil, and thus worthy of death, is to deny an objective fact. Arguing against gravity would be just as illogical.
As some DM put it a long time ago, there are a few million drow on Toril and a good one is one in a billion. The same applies to goodly monsters.
Still not convinced? Still doesn't make sense why you can just ASSUME goblins are evil? Then stop trying to justify a game based on magic and dragons and such, don't worry about it, and please for God's sake just accept the fact that everyone agrees on so as to preserve the integrity of the server and reduce this Out of Character problem.
Lastly, yes, there are times when someone MIGHT not want to kill a goblin for whatever reason. But doing so, manipulating goblins, all this is very, very evil. If your character is ANY Good, I can't think of a situation where you would NOT try to kill a monster while it is around humans (think of the children!) in Lower Sanctuary. If your character is ANY kind of Neutral, I cannot think of any situation where you might even accept monsters as potential allies/friends. Lastly, if you're any kind of evil, you probably ought to have a damned good reason to tolerate these little monsters.
FINAL NOTE FOR MONSTER PCs:
I'm something of a hypocrate. I know. I played a "friendly" goblin for a very, very long time. It bothered me to death, despite its apparent necessity. Of course, that goblin wasn't as friendly as some may think, but that point is an aside.
If you're playing a monster, be one. Do monster things. Eat babies, cause pain, be EVIL. If you're a kobold, don't LOVE things. Kobolds in particular do NOT FEEL LOVE (I need to cite my source, but I'm pretty confident about this being true). Don't make friends. You can have allies, sure, but you are self-centered MONSTERS. Don't lose sight of what you are or you lose a lot of the awesomeness that it is to play a monster, to have monster goals, and to be successful.