Passengers are king for EK (particular HVCs in F) - crew has no option but to tolerate this and this happens pretty much every flight. Complaints, if filed by the CSVs, will not go anywhere. What most likely what happened was this customer would have gotten a purser note, and nothing else.
With regards to the hamburger itself: I always wonder why people waste their calories on planes, especially with the abundance of great food in both SA and AE.