[beobab]

I would suggest that the author is attempting to use the "thinking past the sale" strategy to influence people, and it's causing cognitive dissonance in the readers who disagree with his position.

The typical reader's mind is actively open to learning PL/SQL. To do so, and to follow the examples as is, their mind has to at least provisionally accept the author's viewpoint in order to understand the concept that the example was designed to teach.

When the "false" belief is rejected (for whatever reason), there is a reasonable chance that the example, which was visually and mentally tied that belief, will be rejected, or only provisionally accepted, which could leave the reader feeling like they haven't got their money's worth.

Bland and vague things are accepted as true and assimilated into worldviews much more easily than controversial things, which might be why most examples are boring.