Should pit bulls be baned?

No, pit bulls should not be banned. Banning a certain dog breed does nothing to lower dog attack rates, and actually ends up wasting money on something that isn't working. When you ban a breed it doesn't matter what the temperment of the dog is; how sweet or loving it is. The ban goes by looks alone. Studies have proven time and time again that BSL doesn't lower dog attacks, just attacks by that breed.

Pit bulls can be just as loving and sweet as any other dog, but they can also be aggressive like any other dog. Breed makes no difference; it's the humans that do.

Banning a breed of dog does not reduce the total number of dog bites. Dogs that bite are typically owned by irresponsible owners. Even if a breed is banned, an irresponsible owner may choose to ignore the ban, continuing to be an irresponsible owner with the banned breed, or they'll move on to another breed of dog. Which they'll also handle irresponsibly.
Also, banning pit bulls is not likely to reduce illegal dog fighting. Again, dog fighters are criminals. They will continue to be criminals even with a ban in place. Banning a breed of dog only punishes the responsible owners.