While this is technically true, the reason probably is that the fighting system is really geared towards actual fighting. For that, fighting with other items wouldn\'t make sense. Even in a PvP situation the fight is supposed to end deadly or by yielding, so this also isn\'t suited for throwing tomatoes or doing other things besides fighting.
While I agree that there should eventually be a sparring system, I don\'t think that fighting with anything but weapons would make sense. For RP, you would use /me instead, anyway, because entering a duel just for throwing tomatoes is more tedious than it\'s useful.