The term "safe" should be bifurcated into "safe for human health" and "safe for the general environment".
GMOs are health-safe so far, with complications regarding farmworkers exposure to pesticide. There are serious concerns and reasons to proceed cautiously on environmental safety, especially for genetic contamination of wild relatives of domestic plants and animals.
I think there's a "cool kids" attitude among some, the Ezra Klein types, that tries to show how they're not old-school dirty hippies by expressing love of GMOs.Incidentally, the term "safe to eat" is carefully chosen - many people conflate that as "safe for people" or just "safe", when it's a nice dodge around the issue of farmworkers' increased exposure to herbicides.*
I think there's also a broader issue here that connects to Ecomodernism and its unhealthy relationship to the unnatural. They're not quite hippie-punching, but they definitely want to show a distance. So to them being unnatural is either everything to be avoided on the natural side of the earth that is to be decoupled from humanity, or nothing to be worried about (and maybe even encouraged) on the parts of the planet where the human footprint should dominate.
Unnatural is a something that needs to be considered, not an everything or a nothing. Unnatural means we can't rely on experience and must rely on our feeble brains instead:
To some, [Ecomodernism] carries a whiff of triumphalism. “For a long time, I’ve been a card-carrying pragmatist about environmental issues, but the pragmatism of the Breakthrough Institute is a pragmatism I don’t recognize,” Ben Minteer, a professor of environmental ethics at Arizona State University and a co-editor of the new anthology “After Preservation,” told me. “I don’t see any of the humility or caution that’s such a central part of pragmatism.”That doesn't mean don't go ahead, but rather as John Mashey says, "proceed with caution". And maybe don't proceed in some cases - I wouldn't plant GMO crops in regions where the wild originator of the domesticated plant exists, or where the plant spreads widely as a weed.
Unnatural indicates caution in other ways, with nuclear power as an example. The unnatural concentration of long-term radioactive waste is a problem, not something we have experience or even a geological record to understand how it may go wrong in future millenia. Still, it's a limited problem with a limited geographic scope. I'd put it a distant third in terms of the problems of nuclear power, after the distant second of catastrophic accidents, and the by-far number one problem that nuclear costs way too much.
Considering unnaturalness can be done, pragmatically acknowledging our limitations while not letting them control all we do. Ecomodernism misses this.
*GMOs may also result in farmworkers being less exposed to more poisonous herbicides, and to some insecticides. It's complicated, making "safe to eat" a not very comprehensive vision.