So, I get the reasoning behind this sentiment. You're not "wrong" for feeling this way. I'd be very bummed if he comes back from the World Cup gimpy.
But I do think there are a few things worth noting about the tension in that decision:
In the world's most globalized sport, soccer, the challenges presented by the international form of the game have had 90 years now to mature. FIFA basically invented "big-money players playing for their country", and have had to create and refine an uneasy balance between club interests and federation / governing body international-game interests, which have gotten negotiated slowly over decades... but are now fairly stable. The structures they've created - international "windows" of competition, mandatory release for certain competitive events but not friendlies or youth tournaments, a negotiable balance between "is he REALLY hurt?" vs "Do you REALLY need him?"... it took a while, but now the fans are largely accepting of how it works, where the boundaries are for what's acceptable.
Basketball is rapidly becoming the second most globalized sport, if it isn't already (like, what's close? Rugby? Volleyball? Surely not baseball). But only in the last 30 years. We have a lot of the boundaries of that give-and-take to get ironed out yet. But one thing is incontrovertible: national-team competition is popular, and brings a lot of new fans to your game. Growing the game is something worth investing in, and even though the costs aren't borne equally (because of the randomness of injuries), it does even out eventually. So it's fair for a fan of a specific team to say "I don't care, I don't want the risks". But at a higher level, the NBA as an institution is strongly incented to encourage the teams to permit a release for national team duty... and it's pretty easy to understand why.