It could also indicate that they new coat of paint, as it were, was nearly completely male, or that they tended to have larger families, and/or lower infant mortality. They may just have been preferred as lovers, or had a little more, uh, gas in the tank as it were. For that matter, the preceding Beaker People men may have been polygamous, and not all that numerous.
Sure — those knives, arrows, swords, and clubs had entirely benign uses in that era of universal peace.
I think it more likely that the newcomers were not exactly welcomed, and wars/battles ensued, and the newcomers had superior means and ways of battle, and many majorities of the “native” men were killed. Then, after that, the newcomers became “in charge” and because they had that standing local woman were more likely to chose them as mates than to seek the native men who did not have standing.