The existence of easy calls doesn't get rid of the case of hard calls. I think the damage of making the wrong call when it's hard more than offsets the advantage when it's easy. The labels are less important when scientific consensus is obvious (as in these cases), and they are more likely to get it wrong in cases where a (correct) label would be useful, since it's exactly the cases when it is isn't easy and obvious to determine the scientific consensus that having someone tell us what it is is helpful.