I will generalize here. This thought process does not pertain to all GG's or all men.
Most GG's, that I know, have a "live and let live" attitude. Most guys, that I know, seem to have a "men should act like men" attitude. (Even though all men and women act different from each other.) You might know more about why men act like that than I do.
Just my opinion, but it seems that back when my children were in school, moms came in contact with a variety of quirks that children display. The men usually were not that involved and did not seem to be interested in children other than their own. I just think women get more used to non-standard behavior.
I also think that many men don't want to be supportive of men who wear women's clothes for fear of criticized by other men.