Texan here. The shitty white bread at barbecue places is what we call napkins or mops. Their purpose is to mop up all of the grease and sauce on the plate after you have finished eating your barbecue. They are NOT meant for putting your brisket in and eating like a sandwich. We use the shittiest bread possible because that's what works the best for mopping purposes. Also, it's free. Half of the places just set loaves of it out by the condiments. Then you can grab however many slices you need wherever without asking.