It depends on how you define safety. And, I think the comparison, here, isn't being made to sitting on a couch (which carries its own health risks) but to other

It depends on how you define safety. And, I think the comparison, here, isn't being made to sitting on a couch (which carries its own health risks) but to other professional sports, or maybe its being compared to the safety of even amateur competition across sports. Elite physical competition always carries some risks of injury (even death) - those have to be balanced against the benefits of competing. Definitely there are more dangerous sports that we would consider safe (American football, Brazilian Jiu Jitsu, etc.), where "safe" is defined as "would encourage, or not admonish, our children from pursuing".