Usually because the “Shvigger” has an ear (and full control) with her daughter and influences her, one comment at a time, resenting the fact that this nice boy “STOLE” her control puppet away from her and has the audacity to suggest his wife listen to him once in a while as well.
All these special Shviggers have a special place set aside for them after 120 (or earlier) on account of all the S’char they have accumulated over the years for breaking up Batei Neeman B’yisroel and hurting little hearts and ruining future generations from having healthy marriages due to growing up in broken homes having witnessed under the belt tactics done to their tatty or using “them” the innocent children, in their personal vendetta against an ex or future ex husband.
I cant speak for all, but for many I can. Disgusting!