Well "processed foods" ALSO contain chemicals that are never found in home-cooked food or traditional menus. Many of those chemicals are problematic.

But also "natural" ingredients are often bad as well as certain ratios (e.g. high sugar and fat together, all seed oils, etc.).

For example ALL seed oils are problematic; the only "fats" that is fairly safe are: butter, ghee, and coconut oil. The rest become dangerous with heat (especially unsaturated oils). So ANY food made with cotton seed, flax or similar oils are part of the problem.

Processed foods means "industrial made using ingredients optimized for profit". Using seed oils is cheap. Using preservatives to extend shelf-life so that 1-3 month warehousing and shipping is possible. Therefore these are used.