Not quite sure who your diatribe is directed at. Some might think they know. That's good. But be careful, don't twist your ankle getting off that high horse.
I've personally never shot any .410 loads over 1/2 oz. at a sub-gauge competition. I espouse heavier-than-normal-for-bore loadings in my hunting .410s, but that's a whole 'nuther ball game.
But, give me 20 on a hundred with a .410 bore at a typical S X S shoot at I'll leave the bigger bores home every time. I have won HOA at these shoots before by doing just that. Do I feel like I cheated in some way because I accepted what they offered in the way of a handicap? That'd be stupid. I settled the issue of winners supposing to feel some sort of guilt at winning a long time ago. That's stupid, too. Casual shooters will always be competing with more serious shots at this kind of shoot. It's the casual shooters that usually set these kind of shoots up, anyway. Seldom is the shoot organizer a serious competitor in the event.
It boils down to this. When in Rome, shoot Roman candles . . . .