Puritanical nonsense, and categorically untrue. The Chicago dog, Sonoran dog and chili dog are all firmly cemented in their respective regions, and those are just the first three I could think of.

There's only one condiment that's not allowed near my wien, and that's ketchup. There exists a whole universe of acceptable hot dog condiments otherwise. I'll prepare an extra "fully loaded" hot dog in your name tonight, and you better believe I'm going to savage that wiener, and all its saucy, crunchy and tangy accoutrements, with fervent gusto.

no, that's mayonaise on fries