It’s pretty obvious to me that nothing I, or anyone else, might say, is going to change your mind, since you obviously feel you already have all the answers. You admit that the two brain hemispheres have different functions; you admit that there are people out there who are comfortable with mathematics but less so with imagery, and others who embrace imagery but find mathematics impenetrable; but you say that this doesn’t mean that these people are “left-brained” or “right-brained”. I confess I can’t follow your reasoning here, mainly because I suspect you don’t have any. You ask for evidence, but these are colloquial descriptions, not scientific propositions; “evidence” in such cases simply doesn’t exist; all you have is opinion. You’re arguing about semantics, not science. I suspect you wouldn’t recognise a scientific argument if you fell over one in the street.