Its not like "processing" makes something more or less poisonous.
At scale, processing food often introduces challenges only solvable by introducing chemicals and practices that are considered harmful to humans.
Phthalates become more common in foods the more times it changes hands. Sterilized environments necessary for processing must be sanitized by using chlorine, some of which is exposed to the food itself. Most processed foods have ingredients that are also processed, so the effects of this are compounded. Many preservatives, past and present, have positive correlations with various types of cancer and neurological diseases.
I agree with base premise — you don't automatically start eating healthily by choosing whole foods. But I think it's harmful to consider processing as benign.