Kopet sorry for your loss, but coming from a "pit" owner..... it's the owner..... not the breed. A number of large breeds can and will be aggressive if mistreated or raised improperly.
+10000 99.99999999% of it is the owner. Properly raised, cared for and trained a pit is no more prone to attack than any other breed, and I'm not a Pit fan. But many a dog (of all breeds) have been put down for the lack of a responsible owner.