Well I disagree, but we are all entitled to have an opinion, I rememeber a few years back watching a movie called Deer Hunter in which there were scenes where they were playing Russian Roulette and those guys jumping of mountains in Batman suits are in my view no different to the fool who would play Russian Roulette.
As to them knowing the risk I doubt it as you need a brain to be knowing.
As for training who's going to train them the one's who have gone before are all dead.
To my way of thinking taking action in doing something and really having no idea if you are going to survive or not is different to an activity which is only inherently dangerous because of human error and has no matter how small a margin for error.
What these flying fools have is not a skill it's no frontal lobe to even assess the danger.
I'm not talking about parachuting off a mountain I'm talking about diving off a mountain and attempting guide yourself like a missile almost to the ground.
Being an adrenalin feak and having a death wish are completely different, in my view.
In what they do, the Batmen, the control they have over their destiny is miniscule only unlike all those other activities you referred to in your post, those thrill seekers are people who generally just get good old fashion enjoyment from what they do and for the best part they have complete and absolute control over their activity.
It would be a boring old world if no one took risks but blatant disregard to their safety when the outcome is enevitable is certifiable.
That is, at least, my opinion in the matter.