Science seeks to test new theories about the nature of reality, to improve human knowledge. It often relies on engineering to conduct experiment.
Engineering is for solving human problems at scale. Often based on scientific discovery, but not necessarily. Humans were selectively breeding food for years with no scientific theory of plant genetics.
And we kind of do not have the best track record with engineering things we can’t be sure of in the lab. Generally we do ok with tech, but bio engineering is much different.
What’s more the food industry has lied about what’s healthy for profit in the past. We have a habit of passing the buck to the next generation to cash out now.
Human avarice is enough for me to be against GMO given the plain track record (global warming, aforementioned lies by food producers, etc) of bullshit that was only found to be bullshit later.
That and I hate bananas.