If I were being rude, you'd know all about it, and I would have been banned by now.
Personally I believe it depends on the circumstances. If someone breaks into my home and threatens me and my dog attacks them and the burglar winds up dead, I should not be charged. If someone approaches me with a knife while I'm walking my dog (has happened) and my dog scares them off or attacks them, I don't want to be charged for that either.
Not every circumstance is black and white. Some dogs attack when they are cornered, lost, injured, scared and for a myriad of other reasons.
I do believe that a person should be charged if they have not adequately contained their dog (regardless of whether it is registered as dangerous or not). I also don't believe the dogs owner should be charged if a child ventures on to their property and antagonises a dog they don't know. Same for if out in public when the dog is leashed and under control, if a child smothers the dog without the owners consent (daily occurance here) I don't believe the dogs owner should be charged. Basically if the owner is negligent then the owner should be charged. If it is due to anothers negligence the dogs owner should NOT be charged.