>>17911896The original meaning of the verse is that the girls will be spared from death, which is merciful. Look, I'll even use the Hebrew to show you the original meaning of the text. I will break it down into the basic words and you can translate it yourself.
וְעַתָּה, הִרְגוּ כָל-זָכָר בַּטָּף; וְכָל-אִשָּׁה, יֹדַעַת אִישׁ לְמִשְׁכַּב זָכָר--הֲרֹגוּ.
>V’ata hirgu kol zakhar bataf, vekol isha yoda’at ish lemishkav zakhar – harogu.And–you–kill–all–male–among the little ones–and–all–women–knowing–man–for–lying–bed–man–kill
>Vekhol hattaf banashim, asher lo–yad‘u mishkav zakhar – hakhayu lakhem.And–all–children–of the women–who–no–knew–bed–man–spare–for yourselves
The word is spare, not keep in some sexual perverted sense. The girls were being saved.