However you can also imagine a justification along these lines: There are certain things we humans can do which give us access to unique highly desirable mental states. Some of these are familiar things like falling in love or having children. These are risks but usually perceived as having obvious upsides. There are also other behaviors like drug use or underground fight clubs which also give access to unique mental states but are usually perceived as too risky to encourage. It's easy to put judge free soloing climbing as something like drug use or bareknuckle boxing. But try to imagine that when done correctly and carefully that it could be something much like having a child or working on a math proof for years.