So disclaimer: I don't want to sound like a smarty-pants or anything. its just that you guys are literally talking about exactly what I am studying in school (gender and internet based [digitally mediated] communication).
First, from what I have read men and women use the interwebz for two different things. Men like to use the internet as a way to gather information, women to make connections. This explains why it seems that more women use message boards than men do because most forums are more about those connections than a legitimate means to an end. What is interesting about 3fc is that it serves as both a means to an end and a great place to make serious connections.
Also, the name of the site (as mentioned several times before) has a lot to do with men staying away. Some less mature guys probably see the name of the site and it might as well be called "the super happy vagina-rama forum of estrogen (now served with a side of "feelings")" which makes em run screaming. However anyone immature enough to think that and then run as a response probably would not make a good addition to the forum anyway.
As far as fat-boys being more accepted than fat-girls. Well the answer is: yup, its totally true. Fat guys do get the nasty end of the stick but it's marginal compared to what women go through, from within their circles and beyond them. I do predict that men will feel more pressure in the future, but at least right now they don't feel the heat as bad as women do. The only group of men who face that level of body-discrimination (statistically) are gay men. This is because gay men are judged using the same criteria that straight men use to judge women. What is happening in our society now is because gay/queer people are more accepted (than previously) the negative response to not physically perfect male bodies is spilling over into the heterosexual male experience.
Disclaimer #2: Although I talked a lot about males communicate this way and females that way etc., most scholars admit that communication between the sexes is marginally different at best. You only get truly different communication when sitting directly on top of the bell curve. Some masculine communicators use feminine communication techniques and vice-versa. Despite that men and women do tread the internet in two slightly different ways. Its one of the reasons I enjoy support communities composed mostly of women because they don't spend the whole time trying to give you advice.
I think the bottom line is that you can't find many peers here because our gendered society keeps them away. Maybe instead of focusing on how many men are not here focus on the guys who have over-come whatever gender-related obstacles which would have kept them from being here and enjoy the fact that you have a group of awesome women and equally awesome (yet smaller in number) men to help you through a difficult task.