what distinction is that? What point does a food become ultra-processed? Do foods like kimchi, or honey, or canned or dried beans count?

They use another vague term with little to no meaningful distinction in order to avoid the actual problem, which in this case is overeating and, in general, is foods having too much sugar, salt, and others things added. Additives that are fine in moderation, but are way higher and outside the daily recommended value in these cases.