With humans, there is literally no genetical study that could suggest this. Also, black people have existed for millenniums, and have by nature developed something called empathy

However, dogs are just not as genetically advanced. Them not being totally hostile is something that developed a couple thousand years ago when humans started domesticating them (and that's something you can look up from non Eugenics based papers.)

So the same way we can make people into monsters, we can also make dogs into those, but way easier. And with Pitbulls, you can do those super easily since they just haven't evolved because breeders bred them that way