Lotsa operators can't operate, I agree there... your Mini 14 being accurate at 500 yds with practice, and decent shooter, believable... But you won't see anyone shooting a Presidents 100 style match with a mini 14, the simple reason is because, as a whole, they simply aren't that accurate or consistent enough for that style of competition.
No argument there - but you have to take it for what it is. I run a biathlon, we put 100+ competitors through a 5-7+ mile cross country course with a half-dozen or so shooting stages along the way. No standard positions, no benchrest BS, just shooting from cover, through/around obstacles, that sort of thing. Hitting a man-sized target after humping your gear four miles is a heckuva lot different than shooting from a covered bench with no time limit.
The mini-14 is perfectly fine for that, many folks find out their AR isn't as fail=proof as they thought, many find out their boots/chest rig/mag setup ain't what they thought it'd be.
There's a RunNGun near y'all - there in Georgia, it's a 5k put on by Bruce at Riverside Gun Club if I'm not mistaken. It's a good exercise for the Fudds that have fantasies about participating in some kind of domestic 2A situation.