The fact that it's not real doesn't matter at all. Some people don't enjoy depictions of sex. Maybeit makes them uncomfortable, maybe they think it just looks dumb, maybe they think it doesn't fit the tone of the rest of the game. But your fixation on 'it's not real so what's the problem?' is a weird hill to die on. Furthermore, the game and the things that appear on screen are meant to make us feel things. Maybe it's meant to make us feel entertained, happy, sad, engaged, and a plethora of other things. If we take your argument to its natural conclusion then we shouldn't be feeling anything by playing this game because none of it's real. If you accept that the game and its graphics can make us feel things, then you also have to accept that it can make people feel uncomfortable. Your point that things look more graphic because technology is growing higher-fidelity is a reasonable one, but that still doesn't account for the difference in acknowledging that sex exists and your character maybe has it and actual hard core sex scenes. There is in fact a qualitative difference there. You can argue about how much that difference matters, but it exists.
Also maybe it's just me, but I've never played a game and thought it was better for having hardcore sex in it. I've played Witcher 1 and 2 and the sex scenes there were well done, but honestly I wouldn't have cared if they were removed entirely and I'm always feeling emotionally distant from those who do care about it. Just in general, I don't enjoy explicit sex in media that I'm not coming to for explicit sex. I never got into game of thrones because the violence and hopelessness always put me off, but I do read a series called the Dresden Files, and sex scenes show up there infrequently. And I always just skim past them because they feel like intrusions keeping me from the stuff I actually care about. I do get the principle of it, and I frankly think that as a society we actually should be more okay with sexuality and less okay with violence than we are, but I can't get emotionally invested in any desire for explicit sex in stuff. I think being more comfortable with discussing and touching on it is positive, and being more comfortable with the naked body and being able to accept it as not inherently sexual is something I also think is important. But actual explicit sex? Eh. I don't want it if I'm not looking for it. It's like tomato in a burger for me. Obviously it should be available for people who like it, but when it just comes with the burger then I have to go to the trouble of pulling it out so I can enjoy the good part.
And just to bring up another thing that's been sort of in my head for a little while. I don't really expect the sex scenes to add even theoretical value the game. I can understand the mechanical aspects of what a sex scene can add to a narrative, in terms of character development, ect, but I don't really think Larian's storytelling is at a level where they actually could include sex with genuine maturity and narrative purpose. There are some devs I think could manage it, but I would not put Larian even close to that list.
