We all know it when we see it. Grinding is processing. The nixtimalization process for corn is processing and it's GOOD, because without it you don't get enough nutrients. American Indians did it. You could do it in your own kitchen if you had to. You saute, puree, grind, and mix all the time in a home kitchen. These are processes, but they're not ultra-processing.
You know what I've never heard of anybody doing at home? Hydrogenating. Partially or fully, nobody does that shit in their kitchen. So. First item on the list: hydrogenated oils.
You might buy something like Crisco which is hydrogenated oil, but you'd never make it yourself so yes, even a tub of that "ingredient" is an ultra-processed food as far as I'm concerned. Anything that contains it is ultra-processed, so you can make ultra-processed food in your kitchen by using that as an ingredient; but you didn't make it yourself from normally processed ingredients. Pressing the oil from a seed is normal processing. It may or may not be good; but it's closer to the original healthy ingredient as opposed to something that's ultra-processed.
This is how it's going to go with the list in general--there will be debates about what should and shouldn't be on it; but there should be guidelines about how the decisions are made. Whether or not it's a common process from raw ingredients, normally done in home kitchens is a pretty good guideline to start with.