As an unabashed androphile, I'm very opinionated about male fashions, including hair fashions. I recently disparaged the hideous "fade" hairstyle (aka "Hitler youth" - what does that name tell you?) but on the flip side there is the man bun, or really, just bun, but our culture is obsessed about making sure there is gender differentiation to everything owing to the fragility of masculinity, so fragile there even has to be special man coloring books.
The reason it's such an attractive hairstyle is because a man must have long hair in order to have enough hair to make a bun. And long hair on men is great. Case closed.