Not that I necessarily agree with what she's saying, her comment isn't on where "the study goes wrong", but rather about the fact of the study itself.
In the same way that, for instance, an evil genius can be said to have created a "good" bomb, the "good" here refers to its efficiency, the number of people it can kill, the speed at which it can be activated etc. but these qualities speak nothing of whether the bomb is a good thing - for that question you need to consult the context in which it was made, and the question is of course different and mostly irrelevant to the technical parameters of the bomb. The ethics of killing have nothing to do with how long the blade of your knife is.
Fair point, although I feel that your interpretation may be a bit too charitable. If she had said that the paper should take into account the possible interpretations/implications of the research, then I can understand that. However, she said that the paper itself was unacceptable. I can only conclude that she would prefer no research be done if there could be negative ethical implications.
Actually she says the paper is bad science, and says why in her Twitter feed. She's actually calling for more research, supporting more complex narratives.
Meanwhile here, we're seeing that correlation does not imply causation except when it supports common prejudices and simplistic narratives. Then it absolutely does.
She states simply that it didn't look for proper controls or caveats. As I said in my original comment, I would need an in-depth analysis of why the study is bad. Merely mentioning controls is not enough to convince me, even if the person has a PhD.
And as for her "calling for more research", that is simply not true:
This is one open access article the world does not need right now.
She is literally saying here that it should not have been published.
I don't know what she could possibly mean by 'proper controls'. They're twins. They are better controls for each other (full siblings raised simultaneously of exactly the same age) than you see in 99.9% of sociology or education studies; in some respects they are the best controls that are possible, since you can't run a person through school multiple times to see if they get into college or not. And this study also came with polygenic scores so you can check the genetics directly if you've fallen for handwavy criticisms like of the EEA.
(Heck, she's not even right when she mouths 'correlation != causation', because if you used the PGS to compare siblings, their PGS differences are randomized at conception and the correlation = causation! As far as I can tell, OP didn't do this, just scoring unrelated individuals, but they could have, many other studies have, and she doesn't seem to've checked herself.)
I think blank slate is the common prejudice and simplistic narrative. Calling out the paper as bad science without giving any valid reason is stupid. If the argument had been that a single study is not enough to conclude the author's conclusions (which are not too broad). But one can say that to any study in a new/nascent topic.
But what is in the thread is that such a study should not have been published because it violates ethics, without pointing out the scientific flaws in such a study.
In the same way that, for instance, an evil genius can be said to have created a "good" bomb, the "good" here refers to its efficiency, the number of people it can kill, the speed at which it can be activated etc. but these qualities speak nothing of whether the bomb is a good thing - for that question you need to consult the context in which it was made, and the question is of course different and mostly irrelevant to the technical parameters of the bomb. The ethics of killing have nothing to do with how long the blade of your knife is.