But that's just it! We're talking about two different ways in which people express gender or gender roles: activities and presentation.
Lorileah, you suggest that judging by the "my wife is leaving me" threads, women are intolerant of men who like to bake cakes for example. I disagree. First, if you get both sides of the story from these threads, I'd bet my bottom dollar there is much more that OPs either don't discuss, or they are unable to see because there is not enough communication. Second, give me a man who gets up on Saturday morning and has fun in the kitchen, and believe me most women would not complain. There may well be some activities that in some circles are viewed with a raised eyebrow if a man engages in them, maybe joining a quilting bee in small town America with senior women for example, even though there are no doubt quilting groups in NYC where both women and men participate. But over all I think the division of female vs. male activities has changed considerably, especially now that more women are in the workforce and there are more men and women who are divorced or single and must undertake a variety of tasks in order to be self-sufficient.
As to presentation, I agree that a man who presents feminine is not accepted. Presentation is a major indication of how we see ourselves, and when a man wishes to present as a woman, it looks to those who are unfamiliar with the concept as if he is saying he does not wish to be a man. A guy wearing a man skirt (like Jive Turkey) I think has a better chance to be accepted than a guy wearing makeup and a frilly dress, who aims to present as a woman. And although FtMs might not be as villified as CDers, they do not find universal acceptance and they are often rejected by their families. But to say that a woman who wears pants is masculine is just not true, not in our day and age. Besides, Kendra, in your avatar you are doing a lot more than just wearing a skirt.
So, we have two camps in the presentation debate: those who wish for an outwardly looking gender neutral world and who say there should be no gender separation into how people should present and everyone should be allowed to wear what they please, and those who say there is a difference between how most men and women see themselves, and this will never change.