As I understand it, Summers said something like this: Women are underrepresented in the sciences and math. That may be because (1) they are side-tracked by childrearing, (2) there are innate differences between the sexes, (3) they are discriminated against, or (4) something else. Whatever it is, we should investigate the cause to address the issue.
The statement of possible causes uses the word OR and ends with ALL OTHER. It is, by definition, true. Moreover, there are respectable findings that male and female brains differ. Also, the standard deviation of male IQs is known to be higher than that of females, leading to more super-bright men and more super-stupid men. The super-bright ones might, conceivably, become professors of science or math.
So why crucify the guy over this innocuous statement?
I think the reason is that Summers is the one highly placed person in higher education who sees the risks that the post-structuralists pose to America's system of education -- our trump card in the post-industrial, knowledge-work economy. Now that they small blood in the water -- even over such a seemingly minor issue -- they'd like to try to take him down before he exposes and halts their treasonous efforts.
They cannot be permitted to succeed or it will be generations before anyone in higher education is willing to tackle them again (by which time the U.S. will have lost its economic advantage -- the implicit objective of the post-structuralists).
According to what I read Summers did suggest this:
"Summers offended feminists last week when he suggested that "innate" differences in men and women may help explain why men dominate math, sciences and engineering."