I think a lot of it has to do with how much the kids practiced FT's in High School and AAU. I know a lot of defense isn't played on the AAU circuit, so a lot of it is kids wanting to be flashy without worrying about getting fouled and shooting FT's. They can get better at FT's if they want to but most players are more worried about the rest of their game. A good coach can get them on the right path.
Jason