I think you nailed the crux of the argument on the head though, it comes down to should the guys actually playing the game have the right to make the decision and take the risk. I can understand why owners worry about that type of thing when signing 120 million dollar contracts. They're allowed to force their guys to not ride motorbikes and other things that an athlete might consider is worth the risk. It would just be another clause thing like that, if you want your multi-million dollar contract and be a famous NBA player, all you have to do is give up your right for a medal. If you feel that strongly about it, all you have to do is stay in college until there's a tournament.
What they generally don't do is restrict their players from playing basketball, since that is directly related to being good at their jobs. What's the difference between Paul George breaking his leg in a Team USA exhibition and breaking it in one of those high-level pickup games that happen all summer long? I don't see much that supports one type of offseason ball being riskier than the other.
Do you honestly think the best players in the world go all out in summer pickup games? You think guys are running/falling into the stands? You honestly don't see the difference between playing against practice bodies who are paid first and foremost to not injury anybody vs. guys who are playing for their country on TV with the chance to be known as the best in the world on the line?
George got hurt in a scrimmage doing a routine move he very well might've done in a streetball/pickup game solely to draw "oohs" and "aahs" from the crowd. George's injury was very much so the definition of "freak accident that could've happened playing basketball anywhere."
I never said it wasn't.
So I don't see the point of pointing out how much players feel compelled to go "all out" when that wasn't even really the cause behind the injuries suffered by Team USA this year, including George's. It was all fairly mundane stuff: losing footing (Kyrie), bad defensive plays by the other team (Gay), a scramble for a loose ball (Cousins). That last one happens at every single level of play, by the way.
If you're concerned about players getting hurt in the World Cup/Olympics, why not express that same concern for guys playing in pickup games? If you're playing in a pickup game, your focus is probably more so on entertaining the crowd; you might feel more compelled to do flashier dunks and dribble moves that, while more exciting, could potentially be more dangerous.
Injuries can happen anywhere; there's an inherent risk involved in any physical activity. I don't think players are necessarily at greater risk playing in international competitions than they are simply playing basketball anywhere. It just seems like a fairly arbitrary line to draw.