Not exactly. The term "Terran" was not used in "Mirror, Mirror." It was used in DS9 by nonhuman characters to refer to humans, in the same way that it's long been used in science fiction as a futuristic or alien way to refer to Earth people, or as a less hokey-sounding alternative to "Earthling" (and indeed Star Trek has frequently used it that way in non-Mirror episodes). So the DS9 usage was meant to be aliens' term for humans, not humans' term for themselves. The first use of the term "Terran Empire" was in the Shatner/Reeves-Stevens Mirror Universe novel trilogy, and it was first used onscreen in ENT: "In a Mirror, Darkly." ENT and DSC are the first series to use "Terran" exclusively for Mirror humans, and that's the problem. It's not about whether the Mirror humans refer to themselves that way; it's about the mistaken assumption that Prime humans do not refer to themselves that way. Since all of the first five TV series (counting TAS) had instances of characters using "Terran" to refer to people from Prime Earth, the Federation's Earth, it therefore doesn't make sense to have Prime-universe characters saying "Terran" as if it referred uniquely to Mirror humans.
IIRC, the first on-screen usage of the term "mirror" to refer to that universe was in DSC season one, where Burnham called their ship's displaced counterpart "the mirror Discovery." Which, honestly, feels like a weirder way to introduce the nomenclature than by referring to the universe as a whole.
Yes. It's inappropriately injecting out-of-universe terminology into the universe. The Doctor is not named Doctor Who. The seven stranded castaways never referred to the uncharted desert isle as Gilligan's Island. The Team in Young Justice is not named Young Justice. And nobody ever called Picard and Riker the Next Generation of anything.
Remember those books. Had to believe it was the same people who wrote Prime Directive and Federation (Okay, overload of Easter eggs are the same, but still.) Seems like quite the nothingburger in terms of things that "deserve" fan outrage. Heck, the Discover-prise creates more problems then the use or non-use of "Terran" does.
Yeah. When they call Bashir a Terran, he’s completely thrown off by the term which tells me it’s a word that is barely used in their universe.
"Outrage?" Where do you get that? Criticism is not automatically outrage, and it's very insulting to assume that it is.
Am I to understand that you are too wise to spend time in Facebook groups or too naïve to know what goes on in such "conversations"?
Just because some people act that way doesn't mean that everyone who has a criticism of a show is as bad as they are. That's what people like that want us to do -- to embrace their extreme, all-or-nothing, us-vs.-them mentality and destroy any hope of intelligent discourse. The rest of us should not let them define the narrative. We should be able to discuss the virtues and flaws of a work intelligently and calmly like adults and not hurl ad hominem imprecations like accusing someone of being "outraged" just because they point out a small continuity error. The fact that it's hard to read emotional cues online is why we should give other people the benefit of the doubt, rather than immediately jumping to the most extreme and negative possible interpretation of their state of mind.
For what it's worth, the first time "mirror universe" was (I think) used in narrative was actually David R. George's Plagues of Night; Sisko thinks about Vaughn's counterpart from the "so-called mirror universe."
Yeah, found it by chance at one myself. Haven't seen a lot of internet chatter about it, though, oddly enough.