Yes, I did read the OP. At the end of their post they opened the floor to 'Thoughts, or disagreements?'. Which is what I put forth.
Ah, so you misunderstood the post then, I think.
The post was asking about thoughts or disagreements about the idea of the Y chromosome's "short leg" allowed the Emperor and his fleshsmiths to scribble in some extra instructions (as opposed to a woman's double Xs having no space, apparently. I have little knowledge about genetics and chromosomes).
I don't believe the OP was asking why there weren't any female Space Marines.
Basically, I was asking why is it that this bit of established lore seems to be always questioned over others.
Basically because in a universe of daemons, basically magic, and incredibly advanced medical science that is
basically magic, it seems odd that women are singled out of the Space Marine club.
With all that went into the making of the primarchs and space marines, seems odd to cut your recruiting pool in half.
Compared to the rest of the universe, it seems like it requires a reader to suspend their disbelief a bit.
Which I do, but it's still something odd.