There is no evidence that this is specific to highly processed foods, as opposed to any delicious food. It is true that highly processed foods tend to be more delicious food their price than other foods, but that's about it.
This is one of the problems of this idea of processed foods - many things which don't actually seem to be a significant problem are in fact highly processed, we just don't tend to think of them like that.
Not to mention, there are processed staples eaten all over the world for hundreds or thousands of years without leading to widespread obesity or addiction - bread and beer being some of the oldest such examples.
Many veggies can be delicious with just some heat + salt; though adding a few spices certainly helps.
I'd much rather eat a perfectly cooked skirt steak with home made chimichuri and a side of veggies than a domino's pizza.