Call me paranoid, but it sounded a lot like those letters were made up to scare people and support the authors pov. They were all written in a very similar style; for example, several women said "the only ingredient I did not recognize was sucralose" (not only is the likelihood of recognizing all ingredients in an item of processed food is slim, but they are clearly trying to give the reader the subconscious impression sucralose is some sneaky, dangerous, hidden, unknown chemical additive... like spiking your food with poison. LOL)