I have a sweet shih tzu mix that has lived a long life and still going. Throughout the years there have been times when she snipped at me if I did something she didnt like such as trying to take her food away (growl and snip) or pick her up for a bath when she suspected one was coming. She did it in a way that wouldnt hurt me but warn me off
I shudder to think what an aggressive dog would do if you do something they dont like...it is an ingrained auto response.
It’s been a long time but if I remember what I learned about dogs right, terriers in general were bread to kill other animals, whether it to hunt, or usually to clear out buildings or territories of vermin and threats to crop stores. I’m probably a little off, but even the cute little terriers can get pretty snippy.
The difference is that pits were bread to fight each other, and once they are in full attack mode, they are hard, if not impossible, to call off. They have powerful necks and jaws and they don’t let go, even when they are being killed.