In my opinion, there are several reasons why we see more men debunking.
1) many women are unconformable with challenging those they do not know, this is more true in us older women. Women are more likely to not disagree publicly. They will just leave a convo first.
2) many women with children have more child rearing obligations.
3)more men are more comfortable on computers, this is rapidly changing
There is one area where I am seeing a lot of women speaking up and that is in farming and in trying to educate folks about modern farming, the use of GMO seeds, animal ag and such