It's a rehash of every "Waaaah NTR!!!" conversation on the site, to be fair.
Seeing a woman does not automatically equate to her being an LI.
If she's not an LI, it's not NTR, definitively.
I think that's more like voyeurism.
Not really though. We've already seen her fucking someone early in this game and it wasn't really an issue for most, because it made sense storywise. The main argument is about Viktoria's behaviour and the plot holes it creates. Some people are just throwing the three letter fetish here and there because it fits their agenda or they just ran out of arguments and it's the easiest way to discredit anyone who disagrees with you.
Viktoria is supposed to be a strong woman, who cares deeply about her husband and son, she's not willing to give in to Hellion's advances and she suddenly just lets Savannah do whatever the fuck she wants to her, because she
might keep Ingrid safe, although she doesn't really know if she's still alive and her relationship with her is "son's girlfriend for half a day"...
The whole "my husband and son died trying to save me from a future as a madman's plaything, but now I'll just do it williningly, but it's ok because I'm gonna be a mad(wo)man's plaything and girl on girl is hot... Right? Of course that makes their sacrifice futile, moreso when that woman actually killed my son, but... I'll honour his memory by cumming just by getting fingered by the hand that killed him and then I'll break a mirror or something..." seems a little bit out of character and just an excuse to add some sex scenes with the most popular character of the game...