You're reading things that aren't there. The term 'obscene content' is not used anywhere, so I don't know why you put it in quotes. Perhaps you meant 'offensive content', where the guidelines say, "The game must not include any offensive content including hateful, racist, misogynistic or homophobic content, or anything that would make people feel bad about themselves."
There is no 'close focus' on adult content. It is only mentioned in rule 12. Repeating the quote above, "Any game with adult content must have a content warning at the start of the game." That is reasonable, as we don't want little children being exposed to such things.
I don't think we've ever had a game with adult content, but if anyone does choose to include adult content, then when creating the game's project page, make sure to select the Metadata tab and select Has sensitive content under Audience & Content. itch.io will then filter that game out for anyone that has chosen not to view adult content, which I think is the default.
So, to summarise:
- Any game with 'offensive content' will be disqualified.
- Any game with 'adult content' must have a content warning.
- Any game without 'adult content' is fine.
- All games must be suitable for beginners to text adventures. If they also appeal to children who are beginners to text adventures, then that's a bonus.