The argument about resources still boils down to that "I would have wanted them to dedicate resources to stuff that I enjoy, and not stuff that other people enjoy."
Except, it's not just an argument about resources.
It's an argument about how the focus on such a feature has rammifications on overall design.
- Having all companions being "Pretty" meaning there's no diversity. No depth to companions, no interesting stories to explore from a companion perspective - No dragonborn means you don't get any exposition about how this race fits into the world. No small races means no interactions with how a small race companion might react to say the Duergar or Ironhand Gnomes.
Compare this to DOS2, where you did have the Red Prince, Beast and one of the best characters in the game, Fane. These weren't made with sex appeal in mind, they were just characters from the universe who were written in. But they had depth that made them actually interesting beyond "They make me feel funny in my loins"
- This push for sex is how they assassinated Halsin. People were actually intrigued by Halsin as a character. So they wanted him as a companion in order to learn more about him. But due to this focus on sex, he was made into his entire character being about how he's a massive sex pest and nothing more.
So instead of getting an actual interesting character to explore, one who's a high ranking Druid with a strong connection to the Shadow-Cursed Lands... We get Mr Freaky the Sex Machine...
This is different to "Just don't interact with sex" and comparisons to the Monk class, because it outright changes design of the game outside of "Do you select this option?"
If you don't interact with sex, you still have to suffer from the lack of companion diversity. If you don't interact with sex, you still get saddled with a cardboard cutout in the shape of Halsin instead of an actual character.
Then of course, there's the secondary argument which is about caving to demands of players. Wyll was rewritten from someone actually interesting into the boring nothingburger with no personal impetus in his own story we got. Halsin was as mentioned assassinated when he was suddenly shifted into becoming a companion. Astarion instead of having proper consequences from the bad decision of having him ascend and how that affects his shitty personality (That people want to ignore because he's sexy) had a change to remove it.
Instead of getting to experience what the developers intended, the vision they had of the world and its story... We got garbage that was made entirely to please gooners.
These arguments aren't necessarily "Anti-sex" and advocating that sex cannot exist within the game. But rather that development and design shouldn't revolve around sex. Which harkens back to my initial comment on this thread about the developers being "Unfiltered"
Having sex and gore isn't necessarily bad. So long as it's only used as is necessary and is integrated naturally into the story.
If there is naturally occurring romance options in the game, that naturally leads to a sexual encounter, then having a depiction of the sex can exist instead of a stupid fade to black or worse, the clothed dry-humping crap from Bioware titles (Whereby they find the scene to be important enough to include, but not important enough to not treat it like an absolute joke)
Just like if there is naturally occuring scenes of gore, having it actually depicted is fine. A character like Kniles the Flenser is all about gore and he fits into the world perfectly, having his insanity properly depicted would make sense.
The issue arises when gore and sex start to dictate beyond their station. When characters start being designed because they have to be compatible with standard sexual attraction (AKA: They have to be "Pretty" both designwise and also race wise). Or if you add random BS just as an excuse for gore for gore's sake rather than it being a poignant expression of a key story moment.
With of course, being "Unfiltered" meaning that we see what the developers envisioned. Not what a subsection of players desired, whether they're gooners, prudes or splatterhouse enthusiasts. Since yes, that subsection of players might be pleased by being pandered to... But it leaves everyone else having to deal with what is essentially fanfiction.