I have the deja vu, but when a cockerspaniel bites someones hand they tend to have to get stitches. When an irresponsible owner's pit bull goes apeshit on the neighbors kids, dismemberment and death are much more likely.
Then you combine that with image of the dog being a 'tough-guy' dog and you attract a less than capable crowd of owners who probably shouldn't be allowed to raise a hamster let alone a powerful animal like many bully breeds.
Then multiply that by the fact that many are raised by unscrupulous types to fight and kill each other for the purpose of gambling, and you have a ripe news-worthy story everytime.
Pits don't nessesarily get a fair shake in the media, but its not completely unwarranted.