I think it stems from the fact that many people seem to view functions as all or nothing. Like an F isn't capable of thinking logically, or an S can't think in abstract terms. I think the temperaments are merely subconscious preferences.
Maybe some S types don't like thinking in abstract terms because they find it boring, not because they can't. I know I find dry, overly intellectual discussions to be quite dull and uninspiring so I do my best to avoid them. That doesn't mean I can't engage in that kind of discussion, I just would have to try harder to stay awake.
So it's not that S types are incapable of being intuitive, they just subconsciously (or perhaps consciously) prefer to engage their senses.
But I do think that magical, little N makes some people feel insightful, spiritual, "deeper" than the perceived S stereotype. I sometimes wonder if there are some S types on this board that mistype themselves as N just so they can "fit in and feel special".