I would be tempted to say that the people who don't understand should just be more willing to think spatially instead of being stuck in their other modes. However, then I imagine how it must feel for someone with perfect pitch to try to explain to me how to recognize pitches. I can't do it just by "trying" harder; I don't even understand what it is I'm supposed to be doing.
This is not to say that e.g. people who are not good at spatial thinking shouldn't still try to get better at it. But it does lead me to think that to some extent these learning styles really are, if not genetic, at least deeply embedded in our personalities and early childhood development.