Why Is Chicago Against Ketchup On Hot Dogs?

Watch VideoChicago takes its food seriously.  Maybe you've heard of their pizza? It's deeper than yours. And when it comes to their hot dogs — don't even think about ordering ketchup. 

Chicago's disgust may be best summed up by Dirty Harry in the 1983 thriller, "Sudden Impact."  

"You know what does bother me? You...