So "women" is a collective noun for a group of humans all of whom are female, and "men" is a collective noun for a group of humans who are some mixture of males and females. There's no collective noun for a group of humans all of whom are male? Doesn't that strike you as a bit asymmetric?
I understand that "men" is sometimes used in the way you describe, but I believe that people who do so consider male the default gender of humans.
Brevity is the soul of wit. You certainly lose accuracy, but honestly, nobody wants to read a wall of text.
If you want to presume some sort of conspiracy sexist default supremacist undertone in what I wrote, fine, but I think that says more about you than about me.
I understand that "men" is sometimes used in the way you describe, but I believe that people who do so consider male the default gender of humans.