Your catsup ingredient contains over a half cup of SUGAR negating your "sugarless" barbeque sauce. Might be tasty but certainly not "sugarless" by any means.

Maybe they are using low sugar or homemade ketchup. How do you know? I doubt any how that your facts are correct that ketchup is 33% sugar.

It doesn't really matter. Most of the sugar will burn off on the bbq.

According to the nutrition label on Hunt's ketchup, one tablespoon of their product weighs 17 grams and contains 4 grams of sugar. This means that the ketchup is about 24% (4/17) or almost 1/4 sugar by weight . So 1-1/2 cups of ketchup contains a little over 1/3 cup of sugar. It wouldn't be right to call this "sugarless". If you are truly "barbequing" your meat or whatever, you are using relatively low indirect heat (not directly over a flame, which is "grilling" and not barbequing). Consequently, if barbequing, you wouldn't burn off the sugar. I doubt that you'd burn off the sugar even by grilling. If you burned the sugary sauce that badly, you'd probably make your meat into shoe leather.