This was starlink corn. The EPA approved it only for animal feed because they feared that the Cry9C protein could maybe, possibly be a human allergen. The EPA should have never done a split approval, and the company should have never gone forward with the split approval, and should have either pushed for the full approval or ditched it. As was bound to happen, some of it showed up in the human food supply - when the news hit about 50 people remembered back some weeks and decided that they had an allergic reaction. Testing found that not to be the case. The company removed it from the market (although the large number of people who consumed the corn with not a single documented case of an allergic reaction seems to have shown that the EPA was wrong).
So even though there are lots of non-GMO foods that actually contain allergens and all are fit for human consumption, a GMO food is not fit for human consumption because of a very unlikely, but hypothetical, allergen that has never caused a single allergic reaction.