Not defending your friend, but I think part of it is the association with highly processed foods.
I developed a soy allergy, and I was shocked to learn how much it's restricted my diet. In two years I've found one brand of hot dog buns I can eat. If you you look at almost any fast food restaurants allergen menu you will see soy in almost every single item. Mayo is a effectively whipped soybean oil.
I don't think it's a conspiracy, but it's a cheap additive and seems to have some preservative quality, and a good indication that you're food is highly processed. I eat much healthier now, largely against my will.
I guess we'll have to wait and see, but in the mean time I'll probably pass on the "most powerful rocket ever made in Palestine hit a hospital in a freak accident" and explanation and go with the country that's dropped thousands of bombs in Palestine bombed Palestine.