Sound advice, but it doesn't delineate between a dog who simply replies to irritation and 1 who won't let it go.
Many good dogs who are irritated by something will simply "snap" (literally) and let it go at that. Kind of like we mite yell "stop it now!", or maybe slap a kid. Then it's over.
The problem dogs are those that, even if replying to simple pain (and sometimes, let's be honest, not), won't "let it go". They won't stop the "discipline" - it's not merely a snap, but anything from a series of snaps all the way up to latching onto the offender. In essence, it is a fight rather than just discipline.
There may be something in the wiring of the fighting dogs, that they don't stop when it should be over. Normal dog fights between rival males don't go to the death. It's not about death, it's about dominance, and stops when the lesser dog lays down.
Pit bulls take it further. They don't/can't stop.