Do people actually know the truth of genetic engineering?

With my topic of research I've been reading a lot of articles that say the benefits of genetic engineering can be great, but people reject it with not much research or bad research. For example there was a French scientist that did study on ratsd by feeding them only GMO foods and in two years they developed cancer. However some time later other scientists reviewed his study and found that the breed of rats he used are known to develop cancer I two years regardless of what they eat. So he created this kind of fear of genetic engineering without good research and people disregard the second study. And there's other things too like General Mills started labeling their Cheerios as GMO free even though they never used GMO ingredients in the first place. They're just printing it on their cereal because it creates a feeling of safety from GMO. It's kind of like companies label their food as gluten free even though they use no wheat product so its not possible for it to have gluten and they just label it because people think gluten is this super harmful thing, but it's really only harmful if you have an intolerance to gluten. In addition to all this genetic engineered foods go under years of review by the FDA before people consume it so that they know its not harmful. For example this genetically engineered salmon went under 20 years of review before it was deemed safe to eat. So it's not like genetic engineered foods are dangerous because a lot of studying goes into the science before it's consumed. So in conclusion I feel like some people don't actually know that genetically engineered foods are safe to consume also people just reject GMOs just because of what they've heard.