Holding out is hard....but it gets easier! I'd say if a hunter has minimal bowhunting experience that holding out is not the thing to do...shoot, shoot, shoot....until you have some successful hunts under your belt. After killing mature deer and passing on nice bucks that are young it certainly gets easier.
As far as the seasoned hunter, I feel it's a personal decision. I'd never stop a fellow hunter from shooting a deer (even on my land) that they really want to. My father for example is 66 years old and bowhunting hard. For as long as I can remember he would "hold out"...but in the last couple years has begun to be happy to just shoot deer. I love his decision!
I passed on a nice 4x4 the other day (not big but 130ish) on public land that my father, me, and some other locals hunt. I understand that there's a better chance than not he'll get shot before the time he reaches his full potential, but will be happy for whoever decides to put his tag on him.
I guess what I'm saying is that it is a personal decision and one's ideas of letting deer age should be shared but not forced on others. As far as managing personal farms etc.....just don't invite hunters who are not at the "letting them grow" stage.
I know, I know....easy to say for a guy living in Canada!!!