Because having a fleshly disposition like that of Esau makes it more likely that a person will give up sacred things for illicit pleasures, such as fornication.
١٣ ‏ (‏ أ )‏ كَيْفَ يَتَصَرَّفُ كَثِيرُونَ مِنْ إِخْوَتِنَا ٱلْيَوْمَ كَيُوسُفَ وَٱلْبَعْضُ كَعِيسُو ؟‏