It seems so obvious to us, especially in hindsight. But I reject the notion that it's so obvious "anyone" would question something like this. If an expert says something directly and you are quite sure they said X and not Y, you are not likely to question it. You heard it from the horses mouth. I think that the speaker should try and emphasize INorganic or say it in a clearer way "non-organic" just to drive the point home.