I've yet to see a definition of ultra-processed foods that excludes tamales or includes potato chips.

It seems I'll be healthier if I stop eating traditional homemade Mexican food and start consuming French fries, pulled pork, potato chips, and orange juice.

Small sample but big message. If we can get beyond "it's just calories" in the wide, we can start to have more rational conversations about food in general.

Ultra processed food is shelf stable, often cheaper overall per unit serving (not always, but consider time poor working poor, cost of cooking in the broad sense as well as raw input costs if you want to criticise this) easy to heat, and so attractive for all kinds of reasons to disadvantaged people. Aside from their amazingly addictive effect on us as mouth feel, taste, fat salt and sugar reactions kick in.

For many people, "good calories" are a luxury, unless you mean "cold calories" because high quality can demand prep. Banging an ultra processed package straight out of a box into a microwave which didn't have to be refrigerated is doable.