I haven't looked at Smith yet, but the quote looks like parody to me. Since you seem to take it seriously, I'll respond.

Once you read the relevant passage in context, I anticipate you will agree with me that Smith is serious. Take this paragraph from before the passage I quoted from:

Further, let us return to Gould's criticism that due to "validation" of most other highly used IQ tests and subtests, Spearman's g was forced to appear to exist from then on, regardless of whether it actually did. In view of this ... probably the only place we can look in the literature to find data truly capable of refuting or confirming Spearman, is data from the early days, before too much "validation" occurred, but not so early on that Spearman's atrocious experimental and statistical practices were repeated.

The prime candidate I have been able to find for such data is Thurstone's [205] "primary mental abilities" dataset published in 1938.

Smith then presents the example from Thurstone's 1938 data.

Awfully specific tests defying the predictions looks like data mining to me. I predict that these negative correlations are not replicable.

I'd be inclined to agree if the 3 most negative correlations in the dataset had come from very different pairs of tests, but the fact that they come from sets of subtests that one would expect to tap similar narrow abilities suggests they're not just statistical noise.

The first seems to be the claim that verbal ability is not correlated with spatial ability, but this is a well-tested claim. As Shalizi mentions, psychometricians do look for separate skills and these are commonly accepted components. I wouldn't be terribly surprised if there were ones they completely missed, but these two are popular and positively correlated.

Smith himself does not appear to make that claim; he presents his two examples merely as demonstrations that not all mental ability scores positively correlate. I think it's reasonable to package the 3 verbal subtests he mentions as strongly loading on verbal ability, but it's not clear to me that the 3 other subtests he pairs them with are strong measures of "spatial ability"; two of them look like they tap a more specific ability to handle mental mirror images, and the third's a visual memory test.

Even if it transpires that the 3 subtests all tap substantially into spatial ability, they needn't necessarily correlate positively with specific measures of verbal ability, even though verbal ability correlates with spatial ability.

With respect to self-discipline, I think you're experiencing some kind of halo effect. Not every positive mental trait should be called intelligence. Self-discipline is just not what people mean by intelligence.

I'm tempted to agree but I'm not sure such a strong generalization is defensible. Take a list of psychologists' definitions of intelligence. IMO self-discipline plausibly makes sense as a component of intelligence under definitions 1, 7, 8, 13, 14, 23, 25, 26, 27, 28, 32, 33 & 34, which adds up to 37% of the list of definitions. A good few psychologists appear to include self-discipline as a facet of intelligence.