Not actually a rule I found, and the game is tagged as Adult. It appears to be following the rules.
Hi, I'll point you to this link, where the rules are; https://itch.io/jam/advjam2023/topic/2879403/community-rules-read-first
I'm not sure if it's against the rules, I just suggested it might be if it contains NSFW content.
Those are rules for the forum, not for the jam.
Rule 6 for submissions is as follows: Use content warnings to clearly communicate what players will experience when they play your game. Sensitive content includes - but is not limited to - violence (including cartoon violence), sexual themes, depictions of abuse, depression and suicide.