Behavior can be genetic. Sometimes at wedding you can see which part is the brides (or grooms) family bacause they all have the same worried look and wrinkles shaped by it.
That's the point of the comment. That behavior is as likely to be shaped by genetics as any other trait. There's not as much unique stuff about behavior as people usually think.
This finding is even less surprising, since it could come about by either nature or nurture — whereas height is mostly determined by nature, in the absence of malnutrition.