I've been around
catch dogs (which is the hereditary problem, btw) for 20 years. I've been to a couple pitbull fights as a teen (run by the then local sheriff, btw). I am not for breed bans, and I understand this "mostly" as a population/idiot owner problem with pitties. They are everywhere in big big numbers -- the dogs and the idiots.
I didn't want to tell this story here, but about 5 months ago, I was walking to the convenience store and heard loud terrified screaming up the street. I started to run and two much younger men closer to the scene came out of a backyard running ahead of me. One had a two by four. The other a large screw driver. A
pit who was a friend to all in the neighborhood had latched onto a poodle's throat and was rag dolling it as the owner tried to help her dog. One guy is beating the pit with two by four hammer swings, the other is stabbing it with his screwdriver. The dog does not let go. So knowing a little about handling catch dogs, I tried to use the screw driver as a
break stick. He released once and latched back on. So idiot that I am, I drove the screw driver into the pit's upper mouth with all my strength, lifting the dog by the roof of his mouth and broke free without attacking, thank god.
The poodle died later that day. Her owner had a bad injury to her arm. The pit was not aggressive after releasing, actually seemed quite proud of himself. So yes, it can be incredibly hard to get a catch dog to release if it is doing his terrible thing and the owner is not present.