Who is mentally challenged and who is not?

Folks, who are we to judge who is mentally challenged or not. I know that we all are guilty of categorizing people. But the question is do we know all there is to know. I doubt that. We never will. Who is mentally challenged? Is it someone who walks naked on the streets? If so who says that dressing like the majority was sanity and by the way what is the use of cloths? What if that person is not feeling cold and maybe happier and more comfortable that way? Or is it someone who sees things that we don't? If so who said that what the majority sees was the only reality? Is it someone with a lower IQ? If so we all had lower IQ when we were little. Also who says that IQ is the determining factor in sanity? Those who we consider as to having a lower IQ maybe happier than us. Maybe being happier is being more sane. Who are we to categorize?
          
                                                                                                   By Alazar Desta