The really stupid thing is having companions lose attitude towards you at all. Magic has friendly fire potential, and it just means that you have to position yourself correctly to avoid FF, or face the tactical consequences of having one or more of your party members suffer the same effect as your enemies. The problem arises when these henchmen/followers bear a grudge towards you afterwards, and might outright leave your party. Is it realistic? Probably, but seeing as I could send any henchman to die in lava at my whim (with no protests) it doesn't make any sense that they'd have a problem with getting hit by collateral.
