There wasn’t enough room for women at the asifa. The entire Citi Field sold out with a men only audience. And the Arthur Ashe was added, literally, at the last minute, (after the men only policy was already long set in place.)
Plus, there is a big maaila that a venue be single gender. Sometimes, though, there are additional considerations.
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.