One liberal response to it being unrealistic to have a SJW agenda and consciously shoehorn in trans people into the Baldur's Gate DLC with dialogue that sounds like it came from Tumblr (or to have Rey be unrealistically overpowered in The Force Awakens) is that it's fiction: you can accept goblins and elves (or laser swords and the Force) but you can't accept a trans person (or a super powered woman) in the same fantastic universe, which already differs so much from our own.
For example:
"The Force Awakens has laser swords, planet destroying superweapons and faster than light travel, but you thought a strong female lead was somehow 'unbelievable'?"
"It's odd that in a fantasy game featuring giant ogres and dragons, the appearance of a transgender character is where so many draw the line in terms of realism" (Gamers Flood Baldur's Gate Expansion with Negative Reviews After It Introduces a Transgender Character)
The suggestion is that in the realm of fiction, anything goes and we can write anything we want - since it is fiction, after all.
Yet imagine if a remake of Star Wars: A New Hope had, during the scene of Luke's assault on the Death Star, the Starship Enterprise suddenly showing up for no rhyme or reason, Professor Charles Xavier's face appearing in front of Luke and his saying, with Gandalf's voice, "Use the Force, Harry".
Star Wars, Star Trek, X-men, Lord of the Rings and Harry Potter fans would all be outraged. And, stripped of an ideological lens, virtually all people would agree.
Star Wars might have laser swords, planet destroying superweapons and faster than light travel, but you still expect Star Trek not to appear in a Star Wars movie.
There is a reason why the "Help, help, I'm being repressed!" scene in Monty Python and the Holy Grail is so funny - it is totally incongruous for a medieval peasant to lecture King Arthur about political legitimacy.
Of course, using transphobic slurs in response to Mizhena's inclusion isn't right, but this doesn't invalidate the overall point any more than Muslim suicide bombers shouting "Allahu Akbar!" when they blow themselves up means that other Muslims should never use the phrase.
More:
[discussion] Why are you guys so upset about a transgender character in a DLC pack? : KotakuInAction (where someone makes the point that Mass Effect didn't get hate because the LGBT inclusion was done the right way, and someone else mentions a lot of other games which did the same)