If this was the first in a new series then I would 100% go with this argument. However there will by now be millions of people who grew up with the first two games who will be interested in the sequel to see how the setting and characters have moved on, but whose wants and attitudes have changed from when they were teenagers. Do I think the content of the game should be changed to pander to these people? Absolutely not. Do I think it's worth opening up the game's market to them (and other new players with similar views) by designing the game to modify these scenarios? Absolutely.
For example, have these scenes have a symbol in the dialogue trigger that denotes a sexual content outcome; then have a setting in Options that prevents these dialogue options from appearing. That way adults can self-censor by choosing not to pick them, and can prevent the possibility of triggering them when they are playing with or around people they would rather not expose them to at all. The technology to filter dialogue already exists in the form of Racial and Class tags, and it is already possible to do it dynamically because you can trigger them using Disguise Self to become, for example, a Drow.
