I'm not sure WHY this thread has empassioned our members but a reminder to everyone:
Name calling doesn't make your argument better or your points stick harder.
I think Chevy has a point in general about being more receptive to teaching the new generation... but I'll concede there are some crazy folks and dope heads and other sketchy types I've met that I don't care to take to shoot with. I haven't berated anyone over it but I've certainly politely declined a time or two.
As for instructing, a kid who 'knows it all' would certainly get a different kind of talk before ever going to the range. Firm but fair rules the day. Starting with the range rule "Listen to my commands at all times". I appreciate a newbie wanting to flap his or her wings and fly, but doing something WRONG is doing it WRONG. Clearly there's a line between a certain grip and something unsafe.
If the 'student' lacks the maturity obey the four rules, then I don't see why ANY instructor should or would put up with that.
You wouldn't just hand a kid the keys to your car and say 'go for it.' Nor would you hand a drunk the keys.
Firearms ownership is a right, but it comes with certain responsibilities. If you act irresponsibly around them, you probably aren't ready to use them.