At least in MY personal life - I found my situation the exact OPPOSITE of your thread title. My JW mom was the most supportive person to me when I left the JW cult back in 2003 - she loved and respected me whether I was a JW or not - yet my strict JW elder dad was the biggest asshole who treated me with utmost disdain and judgment all these years since I left the JW cult.
I don't think it's either more mothers or more fathers who shun us- it's probably about equal of both- depending on which parent is the biggest asshole- and for some families it's the mother, in some families , like mine- it's the father. I have just as many friends on this board whose JW fathers shun them as JW mom's. I truly don't think there's any rhyme or reason to it. If you are trying to figure it out blame the WT Society leaders for their cult indoctrination of both men and women's minds which cause this to happen. Kind of how I see it