Crispr is not highly guarded, nor have we learned our lesson about how dangerous it is.
By then, it's far too late to undo those changes. The genetic pollution remains forever.
It is therefore far better to have never done any genetic modification at all, because we simply don't understand how one change interacts with everything else.
Nature has done so much better than we have ~ therefore, because we don't understand nature's decision-making process, and never have, and most probably never will, we should never interfere with tinkering with something extremely and profoundly complicated like DNA.
Selective breeding is superior to humans tinkering with the genome directly.
I agree with your concern, but I don't see this technology as fundamentally different from humans have been doing for hundreds of years. We've already released so many chemicals and materials into the environment that have had many harmful and irreversible effects on the environment. Releasing a genetically modified mosquito does raise concerns, but it's not too different from putting some new chemical into the environment, which we do all the time.
Not to mention complex systems are basically impossible to /not/ meddle with. Fish have accidentally been bred smaller because of practices to prevent depletion by giving immature ones a chance to grow to adulthood. Heck there is evidence that fear of humans is bred in animals.