My short answer is: NO, pitbulls are not evil.
I agree 100% with the other posters who have commented on this issue. Dogs are not born evil, regardless of the breed.
They can have bad behaviors, but there is always a reason for it - abuse, neglect, lack of socialization, genetics, chemical imbalances, medical illness, etc.
Pitbulls really do get a bad rap through the media.
I have never had a pitbull, but I have met several (and have a neighbor who has one). Most of the ones I have encountered have been very nice, even friendly. The exception to this is a pitbull that lives not far from me, whose time is spent chained up outside or with the 2 teen boys that live there - and I've watched as they have thrown rocks at their dog, hit it with sticks and actually encourage it to be mean. (And the animal control does nothing to take this dog from them either!)
I have said it before and stand by it: ANY dog can become mean and aggressive - regardless of the breed.
And another point to consider: Here where I live, in a mid-sized city (about 124,000 people) it has been a growing trend over the past decade and a half - for drug dealers and gang members to own pitbulls. It is their status symbol. They (criminal types) only help feed into this bad reputation for pitbulls. They make their dogs mean on purpose.
A dog who has been made to be mean and attack (purposely done by provocation from their owners) WILL most likely bite one day. It wasn't because the dog was evil or a bad dog. It's because of the owners - who decided that a dog would make a good weapon - and made it into a monster.
It's sad for the dogs and the innocent people who get injured by them.
So what is the real answer? Identify the real culprits behind this growing problem - and then address those issues with tougher penalties and restrictions.
By the way - I am not for banning pitbulls! (Just needed to add that). I just think that if there is ever a complaint filed, it should be investigated and a treatment plan accorded - be it the removal of that dog from the home and training for the dog followed by placement into an appropriate home - or banning that person/family from owning a dog, etc. Stop the dog-fighting. Make it illegal for felons to own any aggressive or potentially aggressive dogs - just like they are banned from owning a gun!
It won't completely wipe out the problem, but it may help to seriously reduce the number of dog bites.
Sorry for the long post, I just wanted to share my thoughts on it.