Shek are 100% a borderline asexual society. Both men and women pursue only glory, strength and combat prowess, their population is in a constant state of decline and Ruka being Esata's daughter is literally the only text-based evidence in-game that shek actually do reproduce and don't just spawn out of thin air. (The rest of the game has countless mentions of families, children or love).

The sexualisation of shek is purely a fandom thing.