“By the Early Bronze Age, 500 years later, these newcomers represented about 40% of Iberia’s genetic pool - but virtually 100% of their male lineages. This suggests that the newcomers were mainly men, and that - somehow - they all but replaced the men living there previously, whilst the local women survived the takeover.”
“Somehow?” It’s obvious that the invaders killed all the local men and took their women by force.
This is a lesson for all ages. If you don’t defend your turf and your women, invaders will come in and take them.