Because these Noshim Tzidkoniyos wives allow their husbands 3/4 hour every day to attend a Daf Yomi, & yet they don’t witness Shas unfolding before them day by day, so they are even more in need of the inspiration of such a Siyum, whilst men owe their wives Hakoras haTov for allowing them to take home time away from their wife every day to attend Daf Yomi.
In other words, to answer your question fixtheworld:- Derech Eretz Kodmo leTorah.