The think with Rottweilers, German Shepard, Dobermans, and Pit Bulls is their genetics are so clouded with aggressive blood lines. They were all bred into being these large, hard mouthed, protective or fighting dogs. The common usage of the Pitt Bull Terrier is to protect property or fight. So the "best" protectors and the "best" fighters are the ones that carry on the genes more so than the cuddle/loving characteristics. In essence we have mostly eliminated the lighter characteristic of a lot of breeds of dogs. Likely close to or the same blood lines that every owner of a pit bull and so on will own whether they want to or not, it is in the dog.
These breeds aren't usually sought out by the normal dog owner, they typically mostly still do what they were bred to do.
As for the Dachshund they're hunting dogs. They take on anything from a fox to a badger so they had to be tough. It is difficult to breed out those characteristics when they were so selective in the past.
That doesn't mean that we're at fault though, these traits served a purpose or the dogs never would have existed. They may not have been a "glorious" purpose though. We like to point the blame at the "now" owners, and yeah bad owners do make bad pets, but it is also in the genetic make-up.
That doesn't mean that these dogs cannot be nice... I've been around a 180 lbs of solid Rottweiler and he was a teddy bear around the entire family, even letting their baby ride him like a pony... The tendencies are still there no matter who the owner is though. All dogs have their quirks, but you can research and a lot of things will be similar within the breed.
I don't really trust a Pit Bull, not around children or the elderly especially. There is always exceptions but, no. If I lived alone or with one other adult human, no other animals or no children I wouldn't rule out owning one. I know what I would be getting into, but the average owner definitely doesn't need to own any of the dogs I discussed - maybe except for the Dachshund or Chihuahua and that's only because of their size.
I hate seeing people pick out a dog that is bred to be this hard working, loyal, but protective breeds, the hyper active breeds, and try to turn them into these whimpering couch potato dogs. I would much rather see the Herding dogs out herding things. The hunting dogs hunting than any of them tearing up the house, the property, the lawn, because they have too much intelligence, energy, and hardened bred instincts and characteristics for their owners to handle. I don't condone PitBull fighting though... that's probably a double standard I can get away with.