Because it's an easy and fast way to destroy your beneficial gut flora, mess up your microbiome and disable the 40-60% of the neuro transmitters active in the gut, not the brain, that contribute to proper mental health functioning. If you ever have to take their anti-botics, you need to replenish probiotics for your gut big time afterward. We have a second brain in our gut, a vital and complex nerve bundle plexus and good bacteria, both which facilitate the health of the release of balanced neuro transmissions and communications. Ones physical, mental and emotional health will more quickly deteriorate once gut flora are compromised. The bad bacteria take over, creating a hostile microbiome that weakens the gut wall causing proteins to leak into the blood, causing more food allergies and autoimmune disorders. These pesticides in and on the food, including healthy prebiotic fruits and vegetables that are GMO, destroy your good gut flora, overall health and they know that.