I have/had similar thoughts. For example: it's all just various hydrocarbons that are going to be chopped up by enzymes, so what's the difference exactly which atom is where?

My guess that the "processed food is poison" people are only by chance hitting on something. They have zero evidence and zero supporting data.

However, I've come to suspect that the gut is a very complex thing, with a computer in it, and highly connected to the brain. Once you start to go down that line of thinking, I think it's plausible that they've identified a real problem. One possibility among many is that "corporate food" is the result of a giant A/B test series over a hundred years that has machine-learned the model embodied in the gut-computer. It's essentially a DoS attack. And so on. Suggest folk consider what if the gut has a neural network with various sensors and subject to training data.