the reason its questionable is because every gene isnt simply an on/off switch to a specific trait.
when we completed mapping our own, we were disappointed to find MUCH less then was expected.
every gene is a trait(or lack of) of like 20 things, most we may never learn of.
so there is questionable long term changes to find out 50-100 years from now.
What you're saying is pretty much correct. The polypeptides that genes code for can have many different purposes in the body. However, the genes that they implant into the genome of genetically-engineered seeds will only express one polypeptide that has one specific function for the crop. For example, there are some GMOs that express a type of organic pesticide called a Cry protein, which is expressed by the genes that they implanted onto the seed's DNA.
Now, there's no saying that it's possible these proteins have adverse effects in our body, but the pesticides expressed by GMO crops are the same ones we already spray on crops (organic crops included). If they're causing problems, it's an issue with the entire way we do farming right now, not the fact that the pesticide is being produced by plant cells instead of being sprayed from a can.
but the nutritional value or safety of gmo crops are only a tiny part of why they are (maybe) bad.
Well, nutritional value is the same for GMOs because they are, for all intents and purposes, the same as any other crop but with an extra protein. You could make some big assumptions and guess that companies cutting some corners by buying engineered seeds also cut other corners and produced less nutritious food, but that doesn't have anything to do with the science used to make the seeds.
and the bee extinctions are now being blamed on gmos and monsanto's round up.
Idk dude, there's not much evidence for that and at this point it's kinda just baseless fear that's causing people to think GMOs cause colony collapse.
there is the corporation issue as well. a few companies on earth control the growth, and sales of most of the worlds food right now. forcing small countries to ONLY grow their patented gmo seeds so they can earn a cut.
since corporations control governments, the only way a normal person can opt out from supporting that, is to not buy the products.
so the LEAST they should have to do, is label gmo stuff. but they lobby to be protected from exposing who and what products they are.
There's pretty much no way to argue against the ethical issues of the people who sell GMO seeds. It's a well known fact that Monsanto forgets over small farms and sues them into oblivion because they grew their patented plant by accident because of seed drift. It's pure evil, no denying that.
However, personally, I wouldn't really consider that a good reason to start labeling GMO crops. There's a lot of baseless fear over the safety of these plants, even though they've been shown to be safe. Genetic engineering has the propensity to help the developing world in a big way too. Golden rice is already being used to help combat blindness in developing countries as a result of vitamin A deficiency, and some people think it's even possible to create plants that act as vaccines for common infectious diseases. How amazing would that be? Food that protects you from polio/smallpox/flu without you ever having to do anything.
Although, that's all not possible unless there's a profit to be made for researching these things, and if people stop buying these plants because they think they're unsafe, then that impetus for research goes away very quickly.