Interesting to see this incorrect line of reasoning about risk laid out so explicitly.

If you're around people who do extreme sports with serous risk, you'll know many people who have this attitude and you'll also know many people who incurred life-altering injuries or died because of this attitude.

A friend of mine who's reasonable and has a higher risk tolerance than me used to paddle with a group of whitewater kayakers who were doing the hardest stuff. 4 out of 7 of them died. She says

the reason she's still alive and so many of her compatriots are not is how she thinks about risk.

People would say things like "there's a 99% chance this will be fine", where "not fine" is fatal and they would then run something that had a 99% chance of working out. She wouldn't do that because, of course, if you regularly take a 1% chance of death, you're going to end up dead unless you're extremely lucky.

Another one is that she would never run something she hadn't observed before, whereas

@danluu a different take is some people care more about getting good, or the thrill, and less about their own life or injury. Certainly though a lot of people should take a step back and realize they are not gonna get famous or paid to do this extreme sport. relax. a little patience will keep you very alive and only limits your potential a little bit.
@danluu like my wife is fairly risk averse but she can still win cat 1 mountain bike races. But then she has professional level fitness. If she wanted to take the next step, might need to take the more insane approach. Too old to be patient!