>Not so long ago women were not allowed in academia; shouldn't the first reaction be "yay!"?

If your ideology is "any differences in outcomes must be caused by systemic discrimination, and we should engage in reverse discrimination to fight it", then this is bad news, because according to that ideology, you should be doing a 180 and discriminating against women. That conclusion upsets some people.

Why should we celebrate a growing gap in any direction?

Women surpassed men in degrees earned over 40 years ago. How long is the celebration supposed to last?

the celebration will last until morale improves

Maybe. I thought we were supposed to think of that as bad?

The second reaction should be to institute a bunch of scholarships for men only, tutoring programs for men only, and so on. Even the elementary school near me a few years ago had a "girls after-school math program" they advertised on a giant banner for the entire time I lived there.

(I don't actually think this, but this is what we collectively did when the "problem" was reversed.)

My reaction was "so not much changed in 20 years, or maybe got more extreme"

The reasons, causes, issues, etc. are too numerous to analyze in a comment. But this wasn't particularly new data for me.

At what point in history has the message "People like yourself are falling behind in a very serious way" ever been met with "Yay!" ?

Also, many Americans are taught that statistical gaps between different demographics are usually a result of some terrible injustice. (It's certainly been true in the past.) Whether or not this is true always or even in this case, I can't really say, but I do understand why the mostly American audience of HN would have a negative reaction...