It is literally for both and intended to mean both, but generally speaking, women have a far easier time passing as androgynous. On top of that, identifying as nonbinary is seen by a lot of people as something "only women do", with anyone presenting as such being automatically assumed to be a woman. Despite being biologically male, when I refer to myself as nonbinary online, people will often attempt to misgender me using female pronouns because they assume calling myself nonbinary means I'm biologically a woman. Thirdly, "masculine" is often seen as the default with "feminine" being seen not as "not masculine"; when a man tries to present as androgynous, it's lumped in with femininity, and traits that should be seen as androgynous are often labeled feminine due to not being masculine. Rather than having masculine and feminine as two ends of a pole, with androgyny being the middle ground, it's often seen as masculine being one end of the pole, and everything else being "feminine" due to this trend of feminine being defined as "anything non-masculine". All in all, this leads to androgyny often being seen as leaning more towards the effeminate.