It seems somewhat odd to me that, instead of addressing possible mechanisms of this correlation, the authors talk about how bullying is an evolutionary trait to pass on genes.

Yeah, that's why I want to get my hands on the study. Maybe the authors did consider that but the article is misrepresenting the study.

The general public and politicians weren't really worried.

Have you not had your morning coffee yet? 😄 The study purports that bullies have more kids, not that people with more kids were/are bullies. It investigated the relation in one single direction, not both.

Wouldn't surprise me. Unfortunately the study is behind a paywall.

I think being assertive and more socially active meaning you're more likely to be a bully is a bit of a myth.

You are reversing the implication that I'm guessing 😉

My guesses are that there ate multiple factors at play:

• less educated people make more kids
• "nice guys finish last" - assertive and more socially active people are more likely to find a partner and make children
• forcing others to follow perceived social dynamics means internal pressure to follow them oneself; having children is a social norm and expectation that is expected to be followed

I'd try and look for papers to see if my guesses hold any water, but time eludes me.