Synthetic chemicals such as DDT and dioxins have instilled a paranoia of man-made supplements. But not all synthetic chemicals are harmful. To rule out all synthetic chemicals is to rule out many proven or potentially beneficial substances.
All the adverse conditions you mention, are caused by various synthetic and naturally occurring chemicals used for agriculture.
Many of the most dangerous substances to man are naturally occurring, such as Botulinum toxin. Should the requirements for safe, sustainable farming practices not be based on safe versus unsafe. There is no logic including or excluding a chemical simply on the basis of natural or synthetic.