To explain: in most parts of the world unless you say no sauce the burger will have sauce added as they make it.
I've found in the US they give you a dry burger and then more sachets than you need of sauce. Which you then take and add yourself.
It's a minor weird difference. I find it an annoyance myself 'why do I need to put my own sauce on, can't they do it when they make it?'. I've always wondered why the US burger joints seem to consistently do it this way. The only thing I can guess is that they want to show you that it's Heinz sauce.