YMMV — anecdote territory

For me, it was probably for the same reasons that some (many? Most?) do drugs, for the moment of mental escape when your entire attention is truly needed in the moment.

While I thoroughly enjoyed adrenaline sports and got off lightly (one clavicle, boxers fracture, one ankle, and a couple of separated shoulders) what actually helped me was years of therapy and mindfulness

I still enjoy the sports, but not at the edge, just being on the mountain/wave/rapids is enough these days

My father was an abusive alcoholic FWIW

Charles Lindbergh [1] has the best answer:

"[W]hen I decided that I too must pass through the experience of a parachute jump, life rose to a higher level, to a sort of exhilarated calmness. The thought of crawling out onto the struts and wires hundreds of feet above the earth, and then giving up even that tenuous hold of safety and of substance, left me a feeling of anticipation mixed with dread, of confidence restrained by caution, of courage salted through with fear. How tightly should one hold onto life? How loosely give it rein? What gain was there for such a risk? I would have to pay in money for hurling my body into space. There would be no crowd to watch and applaud my landing. Nor was there any scientific objective to be gained. No, there was deeper reason for wanting to jump, a desire I could not explain.

It was that quality that led me into aviation in the first place — it was a love of the air and sky and flying, the lure of adventure, the appreciation of beauty. It lay beyond the descriptive words of man — where immortality is touched through danger, where life meets death on equal plane; where man is more than man, and existence both supreme and valueless at the same instant. "

[1] 'The Spirit of St Louis,' Charles A. Lindbergh, 1953

I'm with you, it seems like confused macho posturing from people who seem to have little comprehension that they have responsibilities beyond their immediate desire for excitement, I have no statistics but I'm going good to guess it's a predominantly male sport, the mother's, fathers family and friends and responders they leave behind might have expected more, just because you can does not mean you should.

Perhaps for the same reasons certain people are attracted to service in the military. Some people report getting a massive kick out of participating in active armed combat situations, to the point that civilian life seems dull in comparison.

They are called adrenaline junkies for a reason. That makes me wonder - can we put thrill-seeker in "rehab"? And should we?

It's a challenge mentally? Overcome fear see different places, have different experiences?

I've been skydiving and base jumping longer than I've not been and it's led me to some of the most rewarding experiences of my life.