The issue with genetics is that the aim of breeding in animals is to enhance specific traits be that speed, temperament, size, etc.
When people breed from aggressive dogs there is a higher chance that the offspring will be aggressive too (though obviously there are no guarantees) and if you keep breeding aggressive dogs together the chances are higher and higher each time.
The reverse happened when we domesticated dogs thousands of years ago - we encouraged the friendlier animals to breed together as they made for better companions.
The same can of course be applied to humans, it's just that we don't use the theory and instead opt for (usually!) love. Tall humans having children together will usually (again not always) have tall offspring. Genetics are just as strong in people, we just pay less attention to them until things start going wrong like in the case of the Hapsburg family (How Inbreeding Doomed the House of Habsburg - 23andMe Blog) or the high rates of infant mortality in some Amish communities (No one knew why some Amish children were dying suddenly, now researchers have some answers | CTV News)
I work in horseracing, pedigree and bloodlines are EVERYTHING and it is not uncommon for people to overlook things like temperament when trying to achieve their end goal of breeding a champion.
Of course you have the nature v nurture argument but I've been around racehorses long enough to know that certain families just have a nasty streak in them and that cannot be put solely down to nurture.