system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: The hatred of ketchup among self-professed "foodies" is arbitrary and irrational.

There is no condiment in America more broadly loved and widely detested than Ketchup.  Regardless of whether or not you enjoy ketchup, there are people who will criticize others just for putting it on literally any food.  There are restaurants which refuse to provide ketchup for their customers specifically because they don't feel it belongs on their food, or that it reflects poorly on the personal tastes of the person asking for it.  No other condiment invites that kind of behavior, and the justifications that I have heard for Ketchup's denouncement seem arbitrary at best.  I think mustard is vile, but I don't feel the need to try to make people who do like mustard feel bad about it.

Edit: For the sake of clarity, and so people stop sending the same responses, I am referring specifically to instances where ketchup is singled out for criticism. I am well aware that it is bad form to go to a fancy restaurant and ask for additional condiments because it is rude to the chef. It would be rude to ask for any additional condiments in that case though, not *just* ketchup.
gpt
The restaurant is well aware that it could lose the patronage of people such as yourself when they implement such a rule. A restaurant is a business, and a business' biggest concern should be generating revenue via selling a product or service so theoretically this business should try to appease its costumers in whatever way possible if cost efficient. However, a restaurant with a chef who thinks highly of himself and his food is also akin to an art gallery. The chef the artist, and the meal his art, exhibited to you via your mouth hole. This analogy will surely lose me points, but you wouldn't paint over the Mona Lisa, simply out of respect for it's artistic value. 


That addresses the body of your argument. The title is a different story almost completely.

"Foodies" are (I'll assume) amateur food critics. These "foodies" have just as much say in what you put on your hot dog as Rotten Tomatoes has in your film preferences. 
Criticism does not prevent you from doing as you please. To an extent criticism is arbitrary, but there is almost always some type of rationale to it. In this case, the reasoning behind a hatred of ketchup could be health-related or related to preserving the purity of the "art" you're preparing to consume.