GMO per se are IMO a net good, we're increasing biodiversity.
Also, they are crucial in medicine. Insulin and other peptide-derived treatments are synthesized by GMO bacteria and yeasts (see "recombinant DNA").
Are you sure? Farmers used to have their own subtly different strains of crops at the individual, village, town, and country levels in a kind of expanding concentric ring pattern. Now, at least for cash crops, it's just a few varieties all "manufactured" by one central power.
The current uniformity predates GMOs, it stems from F1 hybrids that are effectively clones, and the legislation that makes it practically illegal to sell or plant non-patented seeds.
Granted.
But in the grand scheme of things, this is as equally an astonishingly new situation as is mechanized agriculture. A hundred years ago, most people lived and worked on farms; now it's like 1% or something like that.
I know that Monsanto's shareholders need to make rivers of dosh, boatloads of cash, money hand over fist, but I don't understand how in practice they've managed to get a vice-grip on everybody's family jewels.
As for glyphosate resistant crops, beyond the currently insufficient science (lots of invalid studies!), I can't see any reason to denounce it or make it illegal).