Sporting definitely seams the worst for back seat drivers, best policy is don't give opinion unless asked. I have been drawn in to helping people who are missing everything, but usually some numpty beats me to it with those immortal words "you are behind that"
Think you're probably 100% right about this being a sporting thing, I would be more than surprised if a "back seat driver" was issuing advice, wanted or otherwise, on any form of trap or skeet layout.
However, those of you who are "suffering" from this unwanted advice must be missing significant quantities of targets if only on the stand in question but if this is a continual problem it might point to the fact that you are a relative novice and are missing more than you are hitting.
Now perhaps you enjoy missing, I might be out of step here but I prefer to break the clay rather than watch it sail on unmolested. Perhaps I'm being contentious but it could be that the person behind you is giving you some useful help. If he/she says "you're over the top of that teal" or "that crosser needs twice that lead" they might be right. Why not give it a try, you've nothing to lose surely, you were missing before and the wisest advice you'll ever receive (and the hardest to do) is
if you miss - do something different!! because if you do exactly the same, surprise, surprise the clay won't shatter this time either.
Never really come across this phenomena myself as I usually only shoot registered comps and, in theory at least, coaching is not allowed whilst you are in the stand so I suspect it is predominantly a club/strawbaler type issue.
So instead of calling them feckwits & gobsh*tes, take a deep breath, try what they suggest and if that results in a kill, smile & say Thank You, if it doesn't work then do exactly the opposite but whatever DO SOMETHING DIFFERENT. Well ether that or have your gun fitted by a reputable gunsmith and go and see a competent coach.
Mr Potter