I don't see how. Some action is a part of the game, but is done carelessly or recklessly. Throwing a ball at an opponent in a manner which is considered foul is, however, going to be excessive by its nature.
The law does state that it is not always a foul to throw the ball at an opponent. I agree and have said as much. It does not, however, state that such a thing can be done recklessly or carelessly. It just says that when it is not careless, reckless, or excessively forceful, it is not a foul. Which also agrees with what I have said: that it does not sound like a foul, but if it was a foul, I would wager that it is excessive force, since it is more force necessary than the game would normally allow. This is the same reason that slight contact to the head or face of an opponent is always violent contact: because there is no time during the match when direct and deliberate contact to the face is a part of the game.