I would not be rightfully upset. They would be well justified in kicking me from the group for trying to bring an Artificer from House Cannith into their Dark Sun game. Artificers belong to one specific setting, just like a homebrew class. You are arguing semantics. My point remains perfectly intact, despite your attempts.
You know Max, I remember you getting upset some weeks ago at people not reading your post and assuming you said things you did not say. Would you mind looking over my post again, and looking at what I said and what I did not say?
I did not say the table was playing Dark Sun. In fact, I gave no setting whatsoever. They are playing "DnD" Generic Fantasy, no setting laid out. If I wanted a setting, I would have said which setting they were playing.
I also did not say "an artificer from House Cannith" I said "An Artificer". Artificer is a generic class. In fact, I can use the rules of Artificers to show you that. In the rules for artificers they have a sidebar, I'll go ahead and post the whole thing. I will underline some things, for clarity.
ARTIFICERS IN OTHER WORLDS
Eberron is the world most associated with artificers, yet the class can be found throughout the D&D multiverse. In the Forgotten Realms, for example, the island of Lantan is home to many artificers, and in the world of Dragonlance, tinker gnomes are often members of this class. The strange technologies in the Barrier Peaks of the World of Greyhawk have inspired some folk to walk the path of the artificer, and in Mystara, various nations employ artificers to keep airships and other wondrous devices operational. In the City of Sigil, artificers share discoveries from throughout the cosmos, and one in particular — the gnome inventor Vi — has run a multiverse-spanning business from there since leaving the world of her birth, Eberron. In the world-city Ravnica, the Izzet League trains numerous artificers, the destructiveness of whom is unparalleled in other worlds — except, perhaps, by the tinker gnomes of Krynn.
So, in fact, according to the rules of the game, Artificers belong to DnD, and they name
SEVEN different worlds where they can be found.
I actually assume you know this list, since interestingly out of all of the major campaign settings (which you consider all of them to homebrew) you picked the only one not on this list to try and make my example seem less reasonable.
So, actually, if that group was in the Forgotten Realms, and they got mad at me, what should be their response when I pull out the book and inform them that, per the rules, the Island of Lantan is home to artificers and my character hails from there. I am now playing a setting approved character. Does that suddenly make the artificer not homebrew?
Please, respond to the actual point. Do not add more text to my example to make it seem false.
Artificers are an official DnD class, supported by the rules, and existing in multiple settings.
If the group is playing generic DnD from the book, with no setting information, and they specifically say they allow all official material, what rules legal reason would they have to say the Artificer is unacceptable?