Because life expectancy is nearly at an all time high. Folks that are 50 or older grew up playing with all sorts of toxic chemicals and most of us are still here and fine. If anything you are more likely to become ill by excessive worrying than the actual chemicals.
Our gains in life expectancy during the last 100 years are probably mostly due to vaccines, antibiotics, and anti-smoking campaigns, completely unrelated to whatever chemicals are in our food. These are separate issues.
