Agreed, pitbulls basically throw every normal behavioural rule of dogs out the window.

German shepherds are definitely more of a "it's how you raise them" breed (unlike pitbulls which are genetically predetermined to kill). They excel at police and protection work which involves training aggression and stranger aversion, but if raised as pets around kids, cats, chickens, etc. they can be completely sweet and docile to all lifeforms.

My childhood GSD protected our house from multiple break-ins and a creep pedophile who followed me home one day (I'm convinced he would've killed the man if I had dropped the leash), but would cuddle with and share his dog bed with our cats and was even gentle with my guinea pig. He knew the difference between friend and foe instinctively.

Pitbulls don't see a distinction. They might know who gives them food or takes them for walks, but there's no sense of loyalty in being able to determine who they should NOT attack. There's guard dogs bred for extreme aggression such as the Fila Brasileiro which will try to attack anyone outside of its family, but also doesn't turn on its family. Wolves and dogs have been pack animals for hundreds of thousands of years, yet pitbulls have absolutely no concept of "pack." They will destroy anything.