I'm not sure you could call this an example of "irresponsible ownership". It really sounds like these were stray/nuisance dogs. Although I couldn't really tell from the article. Perhaps the irresponsibility is in dumping the dogs.

And it also sounds like the animal control office dropped the ball. I do know the lab that mauled my dog was a stray that was running with a pack of other stray dogs. This seems to encourage aggressive behavior.

The poor little girl......

I wonder if she was being supervised while she was in the yard? Did anyone report the bite the other little boy had gotten earlier? Maybe if someone had this little girl would still be with us.