Plenty of them do have "ketchup" as the first ingredient.
Those barbecue sauces include it as ketchup because it's a recognizable ingredient that is generally not considered undesirable by most id est it's considered instead of writing it as the base ingredients they include is as ketchup which can shorten the ingredients list and make it look more "natural". What I'm saying is that the same ingredients in ketchup can and often are listed separately instead of just saying it's ketchup, the same way I can list a slew of things under "natural ingredients" like the aforementioned anal secretions. If an ingredient is considered undesirable and it can fit under a different label they're able to do so. You want your sauce to sound more "homemade" you'd list the ingredients separately as tomato, vinegar, spices, but that's ketchup my guy.
Let's just pick one at random that's pretty popular Sweet Baby Rays:
High Fructose Corn Syrup, Distilled Vinegar, Tomato Paste, Modified Corn Starch, Contains Less than 2% of Salt, Pineapple Juice Concentrate, Natural Smoke Flavor, Spice, Caramel Color, Molasses, Sodium Benzoate (Preservative), Garlic (Dried), Mustard Flour, Corn Syrup, Sugar, Tamarind, Natural Flavor, Celery Seed.
Vinegar, Tomato Paste, Spice, Natural Flavor, put them together and you get Ketchup. The other things listed separately are either mandated by law or because they want to draw attention to them as desirable ingredients. Garlic, Mustard Flour, Tamarind and Celery Seed can all be listed under spices if they wanted to.
Heinz Ketchup ingredients:
tomato concentrate, distilled vinegar, high fructose corn syrup, corn syrup, salt, spice, onion powder, and natural flavoring
Lets see High Fructose Corn Syrup, Corn Syrup, Salt, Spice, Onion Powder, Natural Flavoring, Distilled Vinegar and your tomato base. Tomato Concretrate vs Paste is just ambiguity to the amount of water removed, they're both condensed versions of a tomato compote.
