I'm really not seeing the flow from claiming that basically "selective breeding [some sense of eugenics] could result in biological changes in humans as it does in other animals" to being a proponent for eugenics in either a moral or policy sense. There was an naked counterclaim that it wouldn't work, but honestly that's immaterial to my first sentence, and I don't know that I believe it either. Could you create an overall biologically "better" human? Dubious, if you could define such a thing in the first place. Could you create a human with superior moral or intrinsic value? Definitely not.
It's certainly a completely bonkers statement to drop out of nowhere. There's no context given in that article nor in a few others I found, but I don't think it's unfair to assume there was some sort of context or trigger.
There was a apparently another statement about abortion and Down's that IMO just reads like an amateurish attempt at using absolute utilitarianism to make a profound, off-the-cuff observation based on a pretty ignorant set of assumptions. Yes, it's a stupid statement that makes a pretty generic argument for eugenics with other assumptions, but the core claim of "an action that causes net negative happiness in the world is immoral" is, strictly speaking, not morally indefensible. There is a correcting of facts required, but essentially the same logic is used for the fairly non-controversial (as any abortion, at least) termination of a pregnancy that would only result in suffering and a dead baby. Correcting facts is, I think, much less substantial than correcting thinking.
Is there anything else substantial I didn't see? To use just this as a basis for a declaration of "open eugenicist", to me, just dilutes very powerful terminology that I'm sure many people definitely fit.
Also, as a side note, some of the takes in some counter-articles were absolutely wild. If your position is that (even if you don't recognize it yourself) "Gee honey, I don't think we're in a financial position to try for another baby" is eugenics, it's hard to believe there is actual meaning behind any string of words you manage to get out.
Are you perhaps saying that trying to teach an understanding of a concept like place value or carrying is more complicated than just getting the answer to an arithmetic problem? I have no idea why that should be the case, where would you get such an idea anyway?