No one is claiming Sophia doesn't experience pleasure from sexual activities, at the end of the day she's got a human body with all that entails. But by her own statement, she treats this sphere as completely perfunctory, something she doesn't pay any real thought.
To think someone who doesn't really enjoy something actually enjoyed it because they went along with it, that's just wishful thinking. It's like concluding someone who doesn't enjoy classical music actually enjoyed a concert they've attended at their partner's insistence, because they were ok with going together rather than object. Following this logic the Carnations also have nothing but thrill and fun with what they're subjected to, because they consent to it.
While Sex might not play a big role in Sophia´s life, she is not made from sugar frosting, as you also said. Still you discount that part of her saying this was to rile up Kathleen.
As for the gangbang, we have word of god that she was at least partly into it and what also flies a bit under the radar of the discussion: Abel very rarely orders Sophia to do something and she is at the end of the day his heir. And van Doren does not strike me as a guy giving the future of his medical empire into the hands of a yesman doormat. There is more to it than the obvious.
Sure, it absolutely isn't because Van Doren is old, narcissistic creep who enjoys showing off his power. Not at all. It's a carefully arranged charade and he actually weeps every time he has to subject his beloved assistant and heir to it, to maintain the illusion.
The last sentence was uncalled for, because it is clear you made the argument in bad faith. A part, but just a part, is Abel showing off being one of the big whales in town, yes. But if you read all the stuff about Abel and Sophia more closely, you see clearly that they are NOT there for the reasons the other members are!
Chuck is one of the few who knows that the offical reason the two are in PC is complete bogus! Abel and Sophia have their own black ops labs, testing the new drug at PC (which is a potential danger to being discovered) is completely unnecessary. But Chuck looks at this point only from his own PoV (Abel being another deviant) and I think he underestimates the situation.
We can learn that Abel and Sophia not just dislike the PC leadership, they actually loath them, Chuck the most. The two support Kathleen´s bid for power, but just because it helps to further their own goals, which certainly differ from hers.
I mentioned it before, going by what we can learn throughout the game, Abel and Sophia want either revenge for something that happened in the past or want to screw over Chuck. They might want to take over the club for some currently unknown reasons and it is also possible the two are punchclock villains.
You simply not seeing it does not make it less true! Do not only look at Edwin as your alter ego, think about his possible backgrounds. Then look at what Sophia and the MC talk about and Sophia in general. Edwin also has/had times of serious detachment, he also normally thinks about something, before doing it.
Remember Sophia is creeping out even our residential sadist and schemer Kathleen, no one at the Club beside Abel has something like normal conversations with her until our MC comes around. I posted the screenshot in the earlier post with a reason! Those two can click with each other and that is the reason they find it so easy to talk. And you cannot click with someone you cannot relate to.