Your argument is weak to the point of emptiness.
There are 80 million domestic dogs in the USA.
12 fatal dog attacks is 1.2 deaths per 8 millions dogs or about 6.7 million dogs per human death.
So no, a person would have to be an idiot to even push such an asinine argument as exterminating 80 million animals to save 12 human lives.
On the other hand, urban gang-bangers kill humans at a much higher rate, so I would agree with exterminating all domestic gang-bangers in the spirit of saving human lives. I’m good with that.
Let’s expose the red herring further. Should we kill all Chihuahua’s because Pit Bulls occasionally kill people? That doesn’t make sense, and neither does the premise put forward by Mariner. As for the Gang Bangers. They like to think they are soldiers. Kill them all.