The argument that Space Marines can’t be women because the lore says so doesn’t mean a goddamn thing to me. Lore changes over time as it’s a living document. Before any of that, it’s a fictional world where the entirety of the lore isn’t based in reality.
I promise the world will not end when female Space Marines become a thing. Your life will not materially change. You will still find other media and mediums to get your He-Man Woman Haters club circle jerk on just like you lot always have.
The world will keep spinning. That said, don’t be an incel.