No, they should be the best at a general amalgamation of basketball activities, not necessarily at every one of them. Shooting free throws is such a small part of the game that it's ridiculous that such massive import is placed upon it. Honestly, the fact that the best free throw shooters in the world are generally old out of shape white dudes shows that the skill (and that's all it is) is not indicative of NBA talent; by logical extension, NBA talent is not necessarily going to result in effective FT shooting. It's similar to expecting all NBA players to be the best ball-handlers, 3-point shooters, rebounders or post-up players.