Organic labeling is somewhat useful, since it does provide a list of prohibited fertilizers and pesticides, but I would prefer to simply have a list.
Then you want labeling about patents, not "genetic modification".
It's been the norm ever since the green revolution (modern hybrids often don't breed true http://www.foodrenegade.com/hybrid-seeds-vs-gmos/ ).
They are making an economic decision when they buy and plant any crop, and they are good at making it (it's a low margin business).
Absolutely not. It _completely_ depends on the organism in question. An organism is a complex chemical reaction, nothing like human engineered artifacts. You simply cannot declare _all_ GM organisms to be safe, in all contexts, ever. One has to take them on a case-by-case basis. Some GM organisms are perfectly safe (in certain contexts), others can be harmful.
After labeling: "If GMOs are so safe, then why are they labeled?"
There is literally zero distinction between a GMO and non-GMO ingredient that is not completely fabricated or imagined.