I think that Seimone and Angel have the same issue. They are über talented and have grown accustomed to being the primary scoring threat over many years. A low percentage shot by them may be better than a higher percentage shot from their teammates--but not on this squad. There is room for improvement in terms of efficiency.
Hard to argue with your points, HOWEVER, I think Geno has to be pretty pleased with the progress. The offensive flow in this game was generally much better IMO. Excellent FG%, dominant on the boards, better passes into the post, fewer TO's. Yes, Croatia is not nearly as good as Brazil, or even GB, but I still think USA really showed some progress in this game.
As for Seimone and Angel's shot selection, my guess is that Geno was not terribly bothered by it. I think he wants all his players to take open shots, even if there is a better shot available later in the possession. Why? Because he wants more possessions and more shots in total. That strategy might change vs. Australia, or Russia, but those opponents are weeks away, and I don't think a strategy change will be too difficult to implement with this team.