Dalliard writes as if Shalizi is proposing the lots-of-independent-factors model as his best account of what intelligence is actually like:

In contrast, these results are not at all what one would have expected based on the theory of intelligence that Shalizi advocates. According to Shalizi’s model, g factors reflect only the average or sum of the particular abilities called for by a given test battery, with batteries comprising different tests therefore almost always yielding different g factors. (I have more to say about Shalizi’s preferred theory later in this post.)

Here is one thing Shalizi actually writes about this model (emphasis mine):

Now, I don't mean to suggest this model of thousands of IID abilities adding up as a serious depiction of how thought works, or even of how intelligence test scores work. My point, like Thomson's, is to show you that the signs which the g-mongers point to as evidence for its reality, for there having to be a single predominant common cause, actually indicate nothing of the kind.

It seems to me that Dalliard is, at best, not reading Shalizi charitably.

(On the other hand, I would find Shalizi's argument more compelling if he offered a theory that (1) is at least kinda-credible as a model of how thought works, and (2) doesn't have any underlying mechanism resembling "g", and (3) fits the statistical data reasonably well.)