If it is true that aggregate population differences mean that a majority of the suitable candidates in a field are men, that can make it more important for firms in that field to undertake aggressive efforts to recruit and retain women. Otherwise, firms may end up with an employee base of which only a small minority is women, even when women make up a larger minority of the suitable candidates.
even if the disparities don’t start off as discrimination, you can still end up with an environment in which women who could be great engineers decide they’d rather do something else. A “natural” split of, say, 65-35 could evolve into a much more lopsided environment that feels downright unfriendly to a lot of women. And the women who have stuck around anyway are apt to get very mad indeed when they hear something that seems to suggest they’re not experiencing what they quite obviously are.
Fact is, though, much of the data in Damore’s memo is well backed-up by research. Women indeed are, on the average, more neurotic than men. It’s not an insult, it’s a common term in psychology. Women are also, on the average, more interested in people than in things. They do, on the average, value work-life balance more, react differently to stress, compete by other rules. And so on.