SOME people assume skirts are only for women, others do not! I, for one, don't believe clothes have a gender... to me, they're just clothes. True, there are gender "norms" in society, but everyone should wear whatever makes them happy! If a guy wants to wear a skirt or dress, go for it! If it makes you happy, don't worry what these "people" you mention think.
Sadly they all assume that because that's what everyone is taught even though it is not true. Just as others ha e stated, clothes have no gender. You can't go out into the wild and find a herd of wild clothing to say it's male or female. Sadly everyone seems to think their their ideas and values of how things should be is undeniably important and unmistakably correct that they feel the need to enforce it and anyone who thinks otherwise has gotta have something wrong with them. You know... standard BS stuff.
Let's face it. Skirts look much better on girls (especially with nice and smooth legs) than guys. Guys are generally just on the hairier side and may not look too appealing under a skirt. Hence, people believe skirts SHOULD be for girls
Because whoever claims that is forced into the small box of sexist, derogatory, gender-biased thinking which unfortunately includes the crude stereotypes such as the one above and should get past such simple minded thinking as soon as they possible can.
Well actually skirts and dresses are what men wear in some cultures like in the middle east and Africa the men wear dresses instead of pants because of the intense heat or Scottish wear kilts. But in general I don't see it as a male piece of clothing, nor should it ever be considered one, in my opinion.
They just are in our culture. Women had trouble breaking gender stereotypes when they started wearing pants as well. Today women have pretty much shattered their gender expectations, while there has been very little progress for men. That is why women can wear anything and it isn't considered cross dressing, but if a guy does it then it is labeled a cross dresser.
Unfortunately feminism has only been concerned with women's issues, so just ignores men's issues. Sometimes they even act like men have no issues. That is why there has been almost no progress for men, and why so many men now refuse to be a part of the movement they once believed in.
In order for men to wear skirts and not be seen as wearing women's clothing a better movement for equality would need to emerge. I don't see that happening though. Most guys are just giving up and retreating to their virtual worlds.