I struggle to see that some people have no ability to understand concepts, but it may be true, but I doubt it. If people have some sort of mental disability, than what can I do?
Not everybody is a genius like you.

In all seriousness though, one type of genius is one that IS able to conceive and understand abstract concepts much more easily than the average human being. Einstein and Mozart, for example. Clearly, the opposite of genius is possible in this regard.