I actually find much of what Arthur says here compelling, if what he's saying is the following:

1. Any argument that says all differences are due to biology is silly.
2. Any argument that says that the mere existence of any biologically-based differences is grounds for simply accepting such differences as unremediable is silly.
3. The evidence on the degree to which biological differences explain different social outcomes is very complex and should be interpreted judiciously.

Agreed Arthur.  But I don't believe that Larry Summers was making either of the silly arguments in 1 or 2.  Nowhere do I see him saying all differences between men and women in math and science are biologically based, and nowhere do I see him saying that if there's a biological component to the explanation of difference, we should do nothing about it.  I agree that his presentation was very"loose" and the context of his role as an administrator should have made him far more judicious than he was.  As such, I didn't find his comments offensive or beyond the pale.  I found them to be within the realm of intellectual plausibility, though presented so sloppily and so unaware of his rhetorical position, that they left him open to the objections that have been raised, even if I find the objections of the Hopkins sort to be problematic.

But the bottom line is that he didn't say either of the silly things in 1 or 2. 

Question:  is the following argument the intellectual equivalent of creationism or intelligent design?

"There is some scientific evidence that differences in the mathematical and scientific abilities of men and women, specifically the underrepresentation of women in these areas, may be due to differences in the brain biology of men and women.  We can't be sure that these differences aren't the result of culture (i.e., culture might actually cause changes in brains), but there is some evidence that these differences appear very early in life.  If such differences exist, they do not justify any discrimination against individual women.  In fact, such differences should lead us to look for additional ways to encourage those women who do show real potential in math and science to pursue those fields, thus treating them as individuals of ability rather than members of a group who might, on average, not do as well in these areas."

Let me note my own agnosticism on this issue, due to my own lack of reading in these areas.  However, the argument I lay out above seems to me to be in the bounds of legitimate discourse.