Have GMO advocates scientifically backed up their safety claims?

The burden of proof lies on the side deploying self-replicating novel agents into the environment.

Such things are investigated before they are released, that's the whole point. Thinking that some corporation sticks fish genes into tomatoes and then just gets to sow that wherever they want with no investigation whatsoever is frankly delusional.

So, the burden lies with our ancestors who turned teosinte into corn?

The highlight being the chorus: "mon-san-to let our farmers grow"

So where is the problem? It is not something in realms of scientific discussion. More like with open-source or right to repair. When someone has issue with GMO lot of people assume that it is because of the 'technology' - not the politics.