Okay, there's a lot here. Okay, let's start from the beginning.
John, you're good at taking what I say out of context, and perhaps I'm good at making that very easy. You asked me to remember back to when I was at the 50cc age and think of how I felt invincible. The fact is, I didn't. Well, maybe I did for the first two weekends or whatever, but after a couple flying-W's, a few times flopping over in the mud (one of which ruined my front fender, which caused much crying) and a few scrapes and bruises, I quickly learned how to respect motorcycles for the mean toys that they are. I not only think that riders should start their riding career with minimal safety gear (unless they're in an area with lots of rider traffic, in which case I would suggest learning to ride somewhere else) but I also think that recreational riders should spend at least a year on a bike with less than four inches of suspension travel, early in their development. Of course, that's not going to happen, but there's a reason for it, a safety reason! And by the way, when I say a minimum of safety gear, I mean helmet, boots, long pants, and gloves, with any of the above except the helmet being possibly expendable if absolutely necessary. You can ride without boots if said boots have disappeared into the ether. Just don't make a policy of it!
Like I've been trying to explain, the first few years of learning to ride are important, because that's the point when behaviors are very habit-forming. If you're dressed like a turtle and have a bike that can hit almost anything, you will be more likely (not predestined, but more likely) to ride in a more reckless manner. That's bad! That's why I think you should be able to take your minor bruises, cuts, and abrasions while they're still minor, and condition yourself to reflexively finding the best line in all situations. It's all about incentive. Then, when you have trained yourself to be a good rider in this way, get yourself a good bike that can hit almost anything safely, but now you've got the extra skill to find ways of avoiding things, saving the bike, etc. And you can go ahead and get your shin guards and elbow pads and chest-protector, because accidents will always happen, and now you've got a bike that can make them happen quite severely, in spite of your better crash-avoidance skill. This is the department where I'm severely lacking, and I freely admit that.
John tells us to protect ourselves for a fall, I would modify that to, "Protect yourself against a fall, and then protect yourself for a fall."
I should re-emphasize, I'm not arguing against all riders wearing safety gear! If I were unable to find my helmet, I wouldn't ride that day. I may putt around camp or down the road at 20mph like an 80 year-old granny, but I wouldn't go an an epic 75mi journey. That's an automatic safety procedure your brain does. It knows, "Okay, my head is exposed like a damn cantaloupe, don't do anything stupid." If you introduce some of this kind of thinking very early on (remember, I'm talking only sub-100cc stuff here, and never going as far as riding without a helmet) you will have that "don't do anything stupid" mentality ingrained into the very way you ride.
John, I respect your thoughts and opinions most of the time, but using the word "logic" in that sentence is sinful. Laws exist in order to protect people and property from abuse or damage, even extremely minor damage like annoyance. If there is no one within 30 miles to hear a bike that's running straight stinger (which, I should emphasize, I almost never do!) the sound is not violating anyone's person or property. And if someone's close enough to have the sound be an annoyance, of course I'll pull in the clutch or click it into neutral. Hell, I've been known to turn the motor completely off at times on that bike. I don't know if you think I'm out to just blast people with my stinger and make them think I'm all big and bad. I'd prefer it if that bike were quiet. However, that particular bike cannot be made quiet without killing it's power, so that's why we don't use it much.
Now, for Coop. It sounds to me like what we have here is a failure to communicate. When you said he jumped a rock, it sounded (understandably) like it was intentional. That's what the verb "to jump" usually implies, as opposed for the unintentional verb, "to hit." I'm sorry for the confusion. It sounds like the experience was beneficial for him, in that he'll probably give a lot more respect to the terrain after having an encounter as scary as that. Reminds me of the time the 120 tried to drag me down a mountain into a barbed wire fence when I was 11.
If the kid hit a rock in such a way that he flew through the air and hit a tree, I think its reasonable to say there was some poor judgement involved. Hitting rocks can be okay, if you do it right, but there are limits. It sounds like he explored and went beyond the limits, and I hope this was made clear to him. It's poor judgement to hit a rock that will send you flying in ways you're not familiar with. Now, if you've been jumping that rock for ten years and know it's eccentricities, or if you're boondocking over it through the rock gardens at a speed that you are comfortable with, that's 100% fine.
You have to understand, I had no idea what the context of this "rock" was, so I just had to assume the worst and think he was seeking out rocks in some field to go bouncing off of. I think you'll agree that sounded like bad judgement, given that failure to communicate. Right?
The moral of this whole bloated, massive post of mine is that protective gear has its place, but as I said before, the way you ride and the general level of caution a rider demonstrates is far, far more important (from a safety standpoint) than the gear. And that's a large part of why I think rider fatalities are higher than ever, and whenever you go to a riding park, everyone seems like they don't know what they're doing.