You're right. Joplin isn't densely populated like the East Coast or the New Orleans area. Midwesterners who live outside little towns sometimes forget that.
But let's lower the bar. Joplin is said to have a population of 50,000. How often in the last century have we had a city of 50,000 or more get walloped like that? During a season when many towns and cities got walloped as well? Even factoring in the growth of urban areas, it seems to me that the frequency has increased from what it used to be, even not too long ago.
Does anyone remember the hurricane that headed toward New Orleans, changed course, headed toward Florida, changed course, headed toward New Orleans, went back and forth like that, and then hit the Gulf Coast where it wasn't as populated? I don't remember the year or the exact sequence of movements or the name of the storm, but it struck me as odd.