This does not seem like a super good comparison to me. Sure, corn was genetically engineered from maize. Over the course of like centuries of careful selection and winnowing! By the very nature of selective breeding, any characteristics that would be dangerous to people eating it were consistently removed, because, like, that's how centuries-long selective breeding works.
The change in timescale that GMOs represent is a meaningful difference, because that timescale is itself part of the process of ensuring safety. I really don't feel like this is a crazy point to make.
The GMO conversation is a little bit of a bummer to me, because it seems like it is considered immediately "anti-science," on the same scale as climate change denial or anti-vaccination, to have doubts about the ultimate safety of GMOs. This seems like a surprisingly zealous, black-and-white position for people who are ostensibly arguing for the success of reason to hold.
I think it's worth noting that it's only been fifty years since scientists were calmly assuring people that we didn't need to test thalidomide on pregnant women since science guaranteed it couldn't cross the placental barrier. Science is not, you know, an exact science, it's a series of incorrect certainties. That doesn't mean you should assume it's incorrect, but it is not unreasonable to maintain doubt.
