I’ve read through the study (PDF), and I think there’s a little more to it than people who “can’t abide inequality between any groups of people.”
I’d like to illustrate what I consider an important distinction here. On the one hand, sometimes there really is “inequality between groups of people.” For example, there is good evidence that men have better visuospatial ability than women, and that women have better language ability than men. Therefore, I have no problem “abiding” when most engineers are men, or when women far outnumbered men in my journalism school (in fact, without that imbalance tipping the odds in my favor, I probably wouldn’t be engaged right now).
On the other hand, there is definitely a problem — usually not one anybody can solve, but a problem — when one group of people gets paid less simply because they belong to this group. In this case, there’s not just inequality between the groups, but inequality in the way others treat the groups, even when the individuals in question are equal in skill.
This study made an attempt to disentangle the factors statistically; it didn’t simply point out that women make less than men. In fact, the study shows that the vast majority of the gap is due to factors other than sexism:
After partitioning disciplinary and institutional effects, females earn approximately 14 percentage points less than males (approximately $10,300) when no individual factors are accounted for. When I enter race/ethnicity, marital status, and whether the faculty member has children the difference between men and women faculty members drops to approximately 13 percentage points. After controlling adding human capital variables into the model, female faculty members earn 5.8 percentage points less than males. The difference drops to 4.5 percentage points, or approximately $3,300, after introducing controls for academic rank.
As I see it, the problem with any analysis like this is that there are always factors left unaccounted for. For example, personality: Women might be less assertive than men in asking for raises. So I wouldn’t consider this definitive proof that women face any degree of pure sexism in academia. Still, it’s a serious attempt to answer the question with data rather than emotion, and the author deserves credit for that.