I find it disturbing for a couple of reasons!
Firstly they don't seem to be bothered if they trash their bikes, despite the value of them. Are they loaded......or just fucking stupid? Or both?
And also, considering most of those guys are not young, they seem oblivious to the physical damage they could inflict on themselves.
Back in the mid 70's I used to come off my TS185 and DT400 all the time by pissing about and trying to do wheelies and jumps offroad. I'd hit the deck and bounce around, then just jump back on as if nothing had happened.
Then in 2004 I binned my boy's DT175......and I hit the deck like a sack of shit. I certainly didn't bounce anymore! Took me about 10 minutes to get back on my feet again and I didn't feel right all day!
So the consequences of something like that for me (and guys like me) now at our advanced ages don't bear thinking about. They wouldn't just be serious, they could well be permanent.