There is no mechanism.
These so called scientists are today’s Luddites.
DDT bad
GM food bad
Hydrocarbons bad
No matter the innovation if it helps people, or people enjoy it, it’s bad.
How many years now have they been telling us that coffee is bad for us? Thousands of studies later there are only benefits.
I used to think the same as you.
Then I got Vitamin A poisoning from eating white rice (GMO). To be fair, I took too many supplements and maxed out the Vit A in my liver.
However, I eat rice every day. I had stopped taking supplements and the poisoning got worse. Then I found out that almost all rice has been modified to add lots of Vit A for the benefit of third world kids.
I switched to Non GMO organic brown rice. Problem solved.