All seeds have been ‘genetically modified.’ The modern varieties are very different than those that existed 3000 years ago and bits of genetic code is shuffled around all the time by viruses. The problem with a lot of modern food is not whether it’s genetically modified or not, but who the modifying is done for. “Round Up Ready Soybeans” are horrid, but they also had that conventionally bread celery a while back that caused skin rashes to those who handled it by overproducing furanocoumarins.
The problem in both cases was plants bred for the food producers (farmers) rather than for the food consumers. The problem is one of economics, not technology.