I'm having trouble OOCly understanding the reasoning behind this action by the Princess of Celest... does Celest now preach that killing Nature is wrong? (insert big question mark emote here)

Well, it's not exactly directly in line with Celest's principles, but there's nothing inherently wrong about enemying someone who's doing something that's just generally obnoxious and harmful to -everyone- in the Basin, Celest included.

It isn't a matter of Nature at all. Celest has herbalists in the Paladins. Celestians use herbs, someone wanted to indanger that. Catarin wants her city to have a chance, which definately depends upon them having a necessary resource.

She also didn't want him hiding in Celest, I'd have to guess.

The name of that guy (Locos) means "madmen" in spanish.
Makes me itch.

I'm still confused. Aquamancers destroy herbs with their demenses. Why aren't they enemied for killing off herbs? Unless this one person really threatened the entire herb supply? Help me out here. I feel so clueless.

Id suspect the latter of what you mentioned Rauros.

So it's perfectly acceptable to go around and kill anyone I think is overharvesting "in the name of the Light"? They're threatening the herb supply by "stripping" the herbs.

There wasn't really any "I think" about this. The guy admitted it repeatedly, shouted he was going to do so, was caught in the act any number of times, and so on and so forth (if you want, you can see my Herbs rant in Idiots, and note that Efenel was the one who name-changed to Locos).

http://lusternia.ire-community.com/index.php?showtopic=8494

Link to aforementioned rant.

Aquamancers don't find herbs and say, "Oh, I'll demense here, so that the herbs die! Soon there will be no herbs left!"

Herbs dying is a sad consequence for aquamancer demenses, but not the reason to make the demense.

There's a difference between the unfortunate side effect of a demesne that kills plants and systematically making herbs unavailable to the Basin for no reason other than making the herbs unavailable. One is a point of contention between organizations. The other is, in a word, evil.

Someone post about this in-game if it hasn't already. It would be fun hunting down every Aquamancer with a demense anywhere plants grow because they are effectively stripharvesting.

we have strippers in Lusternia?

I knew someone would say this. I'm just sad it wasn't myself.