Chicago is rabidly anti-ketchup, according to this post on The Takeout. City restaurants post signs proudly saying they don't serve ketchup. Twitter wars bust out when anyone ever mentions Chicago and ketchup.
The Wikipedia entry for "Chicago-style hot dog" flatly states that "the canonical recipe does not include ketchup, and there is a widely shared, strong opinion among many Chicagoans and aficionados that ketchup is unacceptable."
Meanwhile, the Chicago-based pro-ketchup faction is forced to turn to Foursquare for tips on where to find the offending condiment.
And now, the Chicago Department of Transportation is adding "anti-ketchup propaganda" to road signs to make them more memorable, if not memeable.