> Our findings confirm the existence of a robust “Gender Attractiveness Gap” (GAP), with female faces rated significantly more attractive than male faces across rater genders, cultural backgrounds, and portrayed ethnicities.
That's a different thing. They are asserting this pattern exists in all human cultures, not that it's a feature of human cultures (vs other species, also as per the abstract)
> Our findings confirm the existence of a robust “Gender Attractiveness Gap” (GAP), with female faces rated significantly more attractive than male faces across rater genders, cultural backgrounds, and portrayed ethnicities.