While she is being overly dramatic (not really in the light of Native customs and traditions), She is basically right - genetic tinkering is ruining our staple crops, as skyrocketing illness from GMO and gluten allergies attest.
These allergies were almost unheard of in my youth.
My mother got a batch of the Taco Shells made with StarLink Corn. She made three trips to the ER with serious allergic reactions that appeared to be pesticide exposure (mother doesn't use pesticides/herbicides) before we figured out what was going on and the source of the exposure.
For centuries, people have genetically modified purt'near everything, from their selection of a mate, to breeding livestock and pets, to the rose garden and orchard, but have done so by interbreeding existing strains or bloodlines. At least that takes two viable, related, organisms, and mixes that DNA.
But picking and choosing this bit or that and modifying it in a lab, introducing changes and attributes that do not exist in nature, anywhere, is likely to produce results which are less predictable, not more, and like almost every experiment, it seems some 'gets out'.
As for the preeminent skyrocketing food allergy, look no farther than peanut allergies, but the problem there is likely another thing entirely.