I guess we'll be voting for a eugenics program @ SC :D
I don't actually have much against a eugenics program. I think it sounds all fine and good. However, I'm not so convinced that you're making an anti-choice argument, as much as a pro-eugenics argument. The two aren't necessarily mutually exclusive. For the anti-choice part of your argument, I argue that you contradict yourself. It is in fact in your best interest to advocate for choice.
Most of this is in response to your thoughts on the idiocracy experiment and your disagreement with it.
Suppose that Mr. A wants a program that will make the human population stupid and easy to control through selective breeding. He wants people to have no choice over the subject matter. Over time, the system will reach an equilibrium point and acceptance by the people.
You also want a program that changes the human population's genetic material, but with a different end-goal. In particular, you want people to become smart and healthy. However, in Mr. A's view, you do not have a say in the subject matter. The only reason you have a say is because you have the option to choose.
To prevent people like Mr. A coming up with really shitty ideas and ruining society, it is in our collective best interest to protect the idea of free choice. Thanks to it, we have fantastic ideas such as your eugenics program come into existence.
On the flipside, by opening free choice up for debate, you are inviting stupid and dangerous ideas like Mr A's idiocracy experiment that can ultimately damage the society permanently and limit great ideas such as yours. In a world, pre-eugenics era, where free choice can be easily tossed aside based on a person's subjective preferences, your idea needs to compete with all the other ideas and come on top in order for humanity not to be destroyed permanently (`destroyed` in your view). However, if you are confident that this will be the case, then you will no longer need to limit free choice because people will buy into your eugenics program anyway.
By not limiting free choice, your idea both comes out on top and you limit the risk of Mr. A fucking up the society. Win-win. Therefore, it is in your best interest to advocate for your idea through free choice. You have no excuse not to, as you even argued that people would support your idea with the right advertisements and propaganda.
If, over time, people come to accept your eugenics program and want to implement laws that limit free choice to ensure stability in a way that helps people converge towards a point where the few outliers that disagree are weeded out, that's fine. However, in that case I would argue that this is then a consequence of people's free choice, and is not an anti-choice argument any longer. In fact, I would argue that this is how we make choices even in the present date -- we make laws based on the information available to us to maximize well-being (or any other goal, for that matter).
Ps. Your view is also anti-Bayesian, as the information accessible to you right now will be different from the information accessible to us in the future. Therefore, to make an absolute statement that something should be unchangeable and enforced is akin to saying that you have maximal information accessible to you, which is of course not correct.