it's a synthetic derivative of opium. smoking natural opium for recreational purposes is much different than taking prescribed vicodin after you just had surgery. one i agree with, the other i don't. you're comparing apples and oranges here.
Next time a cop takes your plant, say something like "Aren't you gonna take those roses?" or name some flowers or something that are there too. Its a natural plant that grows in the ground. If they are taking the weed plants, and the flowers are the same, why aren't they taking those?