Excellent subject.... Even if the question does not directly pertain to actual hunting...
The old timers I hunt with have told me the same thing about "nubbing" canines, filing them down so the hogs didn't get so torn up... course this was back when you had, basically, straight domestics free ranging...
Where I hunt, the hog is an animal my dogs are meant to control... there is no thought of release, as long as they get it done..
Havin' perty rough dogs... I do admit I have thought about the "nubbing" technique however... pretty extreme... and I sure would hate to lessen my dog's ability to hamstring a bad runner by doin' it...
Just try not to judge somethin' because you don't understand it... have to tell myself that every day....

Just like everything else in life... the more you learn, the less it seems.. you know.