Concepts of gender in clothing are nothing new, but they are also not stagnant. Ancient Roman and Greek societies saw both men and women wearing tunics, togas, and various other draped garments that we would currently classify as dresses. As things currently stand, it is socially unacceptable for men to be seen wearing skirts, as skirts are not only seen as clothing that is feminine, it also suggests that the wearer is feminine. But ultimately, fashion is about self-expression, at least in our modern interpretation, and men should be allowed to express themselves as much as women can when it comes to their clothing. Women can wear pants, suits, and even clothing in men's sizes without anyone batting an eyelash. It makes no sense why this is acceptable for women, but not for men. More men choosing to wear skirts would serve as one small step towards freeing them from patriarchal ideas about masculinity and what it means to be a man. Let men decide for themselves what being a man means to them, skirt or no skirt. 
There are plenty of men who are actively working against patriarchy and toxic masculine ideas, but for various reasons still choose not to wear skirts or dresses. It is possible to work on reaching a goal of gender parity without adopting the styles of clothing of the female gender. More men in skirts might draw some attention socially, as several instances have noted, but it is almost always performative. If men really wanted to wear skirts, they would wear them, as they did for hundreds of years in the past. If they choose not to wear them, that is their prerogative while still working towards gender equality.