What are you trying to say? That all waffle house employees are functionally illiterate? Because that is not what the data says.

That is incredibly state dependent however, looking at https://www.libraryjournal.com/story/How-Serious-Is-Americas..., you are in a different world of literacy if you live in Washington State vs. Texas.

The south happens to be where Waffle House is common.

Presumably the fact they filled out a job application is enough barrier toward literacy. Especially towards words like "egg" or "waffle"

These are totally different versions of the concept of "literacy", though. Being able to read/write abbreviations of "eggs, scrambled", or "oatmeal" falls well below sixth-grade reading level. Literacy statistics involve much more comprehension than reading/writing food orders. Plenty of illiterate people do work in restaurants writing food orders. This is just a systemized way to remember orders, one that is used across all Waffle Houses, so that an employee from one restaurant switching to another will be just as effective, with no cross training or cultural difference.