Why Don't Chicagoans Put Ketchup?

So why are Chicagoans so up in arms at the thought of anyone defiling their beloved hot dog? While there is no definitive reason, Grub Street states that the Chicago-style hot dog simply does not need ketchup and that the addition of this unnecessary condiment ruins the already-perfect flavor balance.

Why is there no ketchup in Chicago?

Why don't Chicagoans put ketchup on their hot dogs? The ketchup prohibition is often used as a kind of test of your Chicagoan-ness – you're not really a Chicagoan if you put ketchup on your hot dog. Former President Barack Obama has said that once you're past eight years old, ketchup does not belong on a hot dog.

Is ketchup illegal in Chicago?

It's not technically against the law to put ketchup on a hot dog in Chicago, but many here would consider it a criminal act to do so. ... As you're putting down the ketchup — no, really, put it down — we recommend digesting the following offbeat Chicago-area rules that are actual laws.