It's easy. For women the core of their power anthropologically lies with beauty. They are judged by it and the core of their power stems from it. That is why there is a beauty industry that centers around women and none for men. That is why women "care" about beauty much more than men. They know that beauty = power.

Women rely on beauty for success much more than men. It is not just in terms of "grades". Even in engineering jobs you can see it, a beautiful woman can get armies of male engineers to "help" her. I literally saw one female engineer get 2 male engineers to spend 3 weeks on a project for her just by virtue of the fact she's a woman.

And she's not even aware of this. Like she thinks people are just "nice". But men are not conditioned to ask other men for this kind of help and we can't expect 2 idiots to spend weeks on a "favor" for someone else.

We live in a world that tries to deny this reality with "gender equality" but these cultural ideas fly in the face of millions of years of biological evolution.

Now that being said. We very much expect that the grades of women should go down when not in person to a degree MUCH MUCH more than men. That is completely is expected. The question now is, why was there even a correlation of better grades and beauty among men in the first place? Why did that correlation exist when men do not rely on beauty? That is the anomaly here.

I think part of the answer is clear. Beautiful men do not rely on beauty for success. They never did hence why when you removed it as a factor the success rate did not change. What's going on I suspect is even more controversial: Beauty correlates with intelligence. This is not an insane notion. We already know that height correlates with intelligence, but it is likely beauty does too.

Edit: I looked it up, https://www.sciencedirect.com/science/article/abs/pii/S01602...

And it looks like my guess was true. This is indeed what's going on.