Machines in every form benefit the owners of the means of production, not the worker that works for someone else. This has been a fact since cottage industry gave way to centralized production at the beginning of the industrial revolution. Machines allow less humans to do more work. That is true of the use of the water-powered forging hammer that replaces a half-dozen men swinging sledge hammers, or of the automated alignment and welding assembly that puts car bodies together without using humans for the bulk of the job.
I'm really surprised that fast food and other low-skill, low-wage work hasn't been replaced by robots already. Companies that sell these products have already figured out exactly how hot the grille and deep-fry oil needs to be, how long the meat needs to be in each and when to flip or remove, and given the crap job that the no-skill worker does of stacking the condiments, a machine probably could apply a slice of lettuce, two slices of tomato, meat, and cheese between two slices of bread to make a hamburger before wrapping it in paper.
Fast food isn't a skill. It doesn't even come close to coffee shop barista, where the customer is already paying a luxury price for a human's touch when making a product that could come out of a machine just about as well. If it costs $200,000 per year to pay employees to work a fast food restaurant, and that cost can be reduced to $60,000 per year by the introduction of a half a million dollars of machinery that will last for a decade, these companies would be nuts to not replace workers with robots.