Let's assume that's the not the case - I think it's reasonable to say that highly processed foods are bad because they lead to health problems, no? Which means, in practice, one would want to avoid them or at least severely limit their intake.

And if we assume that is the case, that these are just effects of obesity? Well, then... since highly processed foods (in observed, population wide practice) lead to obesity then.. they should still be avoided or severely limited, as to avoid obesity and therefore avoid those obesity related health risks.

So the practical take away is the same, whether we go "processed food = bad" or "processed food = obesity = bad".

Sure, one can become obese on a diet of minimally processed foods (but in practice it's much less likely) and one can maintain a healthy weight eating lots of processed foods (but in practice it's extremely hard to do). But what does that actually change?

If its actually just obesity irrespective of processed foods, would the correct takeaway be "go ahead and eat all the junk food you want, just don't go over your calories (even though these foods are designed to make you want to keep eating and you'll be hungry and go through insulin spikes and in practice pretty much nobody eats like this and maintains a healthy weight)"?