There seems to be a huge crowd of unhinged anti-SJW warriors who hated the one (admittedly rather clumsy) 'transgender' line included in Beamdog's SoD so much that they now feel compelled to complain about Beamdog everywhere...
From what I remember, it was a lot more than that one line.
Initially, the writer of
Siege of Dragonspear took a swipe at
Baldur's Gate on account of its sexism and suggested that it was up to her to correct that in the add-on, which she followed up with something pointlessly antagonistic like, "If people don't like it, too bad."
That generated a lot of ill will before anyone even got a chance to play the add-on, and it guaranteed that a lot of people were going to go over it with a fine tooth comb and interpret anything that looked like it might be pushing an agenda in the most ungenerous way possible. That impulse seemed to coalesce around the poorly written trans character, but I vaguely remember complaints about the player being chided for mansplaining and racism, too. Then there was also a joke that seemed to be baiting Gamergate, which only made the whole situation worse.
Once the controversy erupted, the add-on's writer wrote that she didn't care if her attempts to insert diverse characters into her games came across as forced and that not only was she proud to be an SJW but that she intended to continue making "social justice games" (which, if I recall correctly, was the actual phrasing she used).
Compounding the problem, the game shipped with broken multiplayer and numerous other bugs. The developer claimed that the bad user reviews were a result of the presence of a minor trans character and a Gamergate joke and asked players for good reviews to balance them out. A developer asking for good reviews would be bad enough, but given that there were a lot of complaints about how buggy the game was, it looked worse.
None of this is intended as support of people who are already giving the game bad reviews to hurt Beamdog. (I'm glad an Enhanced Edition of
Planescape: Torment will be available, and I'll be buying it.) However, the rollout of
Siege of Dragonspear was a debacle that turned off a lot of people who wouldn't necessarily have a problem with trans characters.