True, it is the behaviour of the humans for basic greed of betting on dog fights that victimized the animals. What you fail to understand is that either criminals (guarding drug ops) or inexperienced and naive owners cannot be trusted if they get a hold of a dog they cannot control. This ends up very often in another person's pet being mutilated, another adult or child. It is not the dogs fault, but the pet or person is still severely injured or dead. It happens constantly.
As for your facts on pit bulls ... they are absolutely not true. Other dogs can be dangerous, true. But pit bulls were a mixture of dogs that were bred specifically to fight. They were genetically bred to fight because of their tenacity. You cannot stop an attack, The reason they are used to fight is because they win! Backyard
Great owners = great dogs. But how can you make sure ONLY qualified owners have them?  Too late if it is ripping up your pet/child because it escaped from an irresponsible owner.