There were article headlines and NPR shows about this like this 15 years ago.
monoculture is bad but bedwetting about le scary science corn is real dumb. Corn only exists in its current human-edible forms because of genetic changes from selective breeding.
Monoculture isn't just 'bad'. It is a threat to food security. A virus can wipe out your entire harvest. Any sensible government is going to be scared.
It would likely also drastically reduce the number of heritage and heirloom varieties being grown as they are outcompeted by the GM variety, so it destroys genetic diversity for the whole crop.
The US corn stock is basically like 1-2 clones of a single plant from 1949. Its super terrible and keeps farmers captive. GMO plants can be good, but their current state is an abusive monopoly that threatens food supplies and does live tests on hawaiian children.
GMO is bad because agri-capital is using it to gain a literal gun-to-your-head monopoly on the most requisite material for human life
Mexico is in the right to beat their drums against the encroachment of the alien interests of u.s capital.
There's plenty of horror stories from u.s smallholder farmers that very had the fucking wind blow some GMO plant jizz into their fields and cause patented agricultural commodities to accidentally grow in their fields leading to the demons known as corporate lawyers litigating them out of house and home.
Down with American food imperialism!
Archive link for the National Geographic article
https://archive.is/ea3E8
Isnt american corn super high in sugars? I can understand wanting to keep native corn species dominant within your country for dietary and economic concerns but GMO bad is silly