This is exactly what's been going through my mind following the threads on this issue today.
> That makes no sense unless everyone is stupid.
I think this is a false dichotomy. The offended comments seem to be offended by arguments similar to those in the manifesto rather than those in the manifesto. E.g. offense is rightly taken at the argument "biological differences explain job preferences" while the manifesto argues "biological differences explain job preferences [in part]".
So rather than [A] being being offended by something that is not offensive (i.e. stupid) or [B] the manifesto being offensive I think we're left with [C] people being rightly offended by something that's not in the manifesto.
With this the argument becomes: That makes no sense unless people have bad reading comprehension
Which I happily accept :)