First off, I think the term "man-made" in this context is highly misleading. In this context, I think most people would see that headline and think it means cancer was designed and manufactured by humans. Sounds like a conspiracy theory, similar to HIV being made for nefarious purposes. Perhaps a re-wording is needed, like "Researchers finally confirm that cancer is far more due to human-caused external factors than previously thought."

Like you, I thought this was a no-brainer to begin with. One thing not addressed in this article is exposure to nuclear radiation.

These include the relationship between colorectal cancer and diet, skin cancer and sun exposure, esophageal cancer and smoking, cervical cancer and the human papilloma virus.

I like how two of the 4 causes they list have zero to do with chemical exposure.