Immediately backing off to "I know it when I see it" really doesn't help your case that UPF is the right way to categorize unhealthy foods
There is 2 ways to have that discussion:
1. Ultra processed food is a media hype -> totally dismiss it
2. Ultra processed food is often used without proper classification and would be more useful to have well defined sub categories
It’s basically a wildcard, “ultra processed food” is a classification of nothing and everything. There’s nothing inherently bad about processing food, lots of food is terrible for you but that’s unrelated entirely.