The immediate but largely irrelevant answer to your question is... plenty of fantasy novels feature sex. Most of them, I might add.
There is explicit sex in Perdido Street Station, by China Mieville.
And in many books from The Magicians series, by Lev Grossman.
And in some passages of The Kingkiller Chronicle, by Patrick Rothfuss.
And pretty much everywhere in A Song of Fire and Ice, by George Martin.
And here and there in many Cosmere novels, by Brandon Sanderson (I remember at least some in the Mistborn saga, both era 1 and era 2)
There is definitely sex, and quite explicitly so, in the Rivers of London series (by Ben Aaronovitch) and in the Dresden Files series (by Jim Butcher).
There are a few explicit sex scenes in the Broken Earth series, by N. K. Jemisin.
Oh, and there is TONS of sex and actual general debauchery in Elric of Melniboné, by Michael Moorcook.
I hear there is also sex in the classic Conan stories, but I haven't read those, only saw the cheesy (but amazing) movies :P
And oh my gold the sex in The Witcher series, by Andrzej Sapkowski!
And I could go on and on...
Sex was also very much present, albeit never explicitly described, in many classic Forgotten Realms novels by R. A. Salvatore... at least the one involving Drizzt Do'Urden and the Drow underdark society.
There is sexual innuendo pretty much everywhere in the Discworld novels, by Terry Pratchett :D
Etc...
So yeah, if you ask me, there is sex in a LOT of fantasy stories :)
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That said... this matters little for Fantasy World.
To use technical jargon: Fantasy World fosters a narrativist agenda, rather than a simulationist one.
In plainer words: it fosters the kind of fantasy stories that the participants create for themselves, rather than celebrating a specific work or genre by closely adhering to it.
Fantasy World structure is meant to produce dramatic stories where the protagonists are people. It supports this narrative goal by conjuring (through the rules) emergent character arcs and storylines focused on the protagonists Problems and Doubts, and their common goals and hopes and fears... and usually by challenging all of these with the external world surrounding them: the people living in it, those people's own dreams and fears and goals and flaws and virtues.
Stories that revolve around people tend to also revolve around people's relationships with other people. Which often means sex: love, desire, lust, romance, rejection, heartache, hope, etc... all the good stuff. Kingdoms rise and fall for this stuff. Just think about the epic fantasy that was Homer's Iliad :P
That said... while FW is deeply rooted into people... the game is not, in and of itself, focused on "sex".
There are no "sex moves" like in Apocalypse World, for example.
And the only references to sex in the whole book are to be found in the 2 moves you noticed... and they are there because, well, because they represent (like all moves) narrative clichès and stereotypes :P
One allows the PC to use magic and performance art to crank an audience emotions overboard: sex is the most obvious, natural, and expected outcome. The other does exactly the same, but through the use of rhetorics and passion and fervor.
That said, the mere mention of the possibility for sexual content doesn't mean that it has to be present or central at your table. Or that you have to be graphic in expressing it. It's in the moves to remind the Players that the narrative option exists, then trusts them to do whatever they feel like with it.